Organic electroluminescent element and electronic device

ABSTRACT

The compound represented by formula (1):wherein A, B, R1, and R2 are as defined in the description,provides organic electroluminescence (EL) devices having a high emission efficiency when operated at low voltage and a long lifetime and electronic devices including such organic EL devices.

This application is a continuation of U.S. application Ser. No.16/077,966 filed Aug. 14, 2018, allowed, which is a national stage ofPCT/JP2017/005168 filed Feb. 13, 2017 and claims the benefit ofJP2016-029057 filed Feb. 18, 2016.

TECHNICAL FIELD

The present invention relates to organic electroluminescence devices andelectronic devices comprising the organic electroluminescence devices.Further, the present invention relates to compounds usable as materialsfor organic electroluminescence devices.

BACKGROUND ART

An organic electroluminescence (EL) device is generally composed of ananode, a cathode, and one or more organic thin film layers sandwichedbetween the anode and the cathode. When a voltage is applied between theelectrodes, electrons are injected from the cathode and holes areinjected from the anode into a light emitting region. The injectedelectrons recombine with the injected holes in the light emitting regionto form excited states. When the excited states return to the groundstate, the energy is released as light.

Many researches have been made on the applications of organic EL deviceto display, etc. because of its wide selection of emission colors byusing various emitting materials in a light emitting layer.Particularly, the research on the materials each emitting three primaryred, green, and blue colors has been made most actively, and theintensive research has been made to improve their properties.

One of the most important problems involved in organic EL devices is toachieve a high emission efficiency. To obtain an organic EL device withhigh emission efficiency, it has been known to form a light emittinglayer by doping a host material with a several percent of a dopantmaterial. For example, the compounds described in Patent Literatures 1to 5 have been known as such materials for organic electroluminescencedevices.

CITATION LIST Patent Literature

-   Patent Literature 1: KR 10-2014-0115636A-   Patent Literature 2: CN 101104676A-   Patent Literature 3: US 2012/0181520A-   Patent Literature 4: WO 2015/041358-   Patent Literature 5: U.S. Pat. No. 7,838,130

SUMMARY OF INVENTION Technical Problem

The inventors have studied the compounds disclosed in Patent Literatures1 to 4 and have found that there is room for further improvement on thecompounds in view of the emission efficiency and the lifetime.

Thus, an object of the present invention is to provide an organic ELdevice having a high emission efficiency at low voltage and a longlifetime, an electronic device comprising the organic EL device, and acompound which provides the organic EL device.

Solution to Problem

As a result of extensive study for solving the above problem, theinventors have found that the problem is solved by using a compound offormula (1), wherein a specific substituent is introduced into adibenzofluorene skeleton having a spiro atom, as a material for organicEL devices.

In an aspect of the invention, the following (1) to (4) are provided:

(1) A Compound Represented by Formula (1):

wherein:

each of A and B is a substituted or unsubstituted naphthalene ring or asubstituted or unsubstituted phenanthrene ring;

a substituent on the naphthalene ring or the phenanthrene ring is afluorine atom, a cyano group, a substituted or unsubstituted alkyl grouphaving 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkylgroup having 3 to 20 ring carbon atoms, a substituted or unsubstitutedalkoxy group having 1 to 20 carbon atoms, a substituted or unsubstitutedfluoroalkyl group having 1 to 20 carbon atoms, a substituted orunsubstituted fluoroalkoxy group having 1 to 20 carbon atoms, asubstituted or unsubstituted aryloxy group having 6 to 30 ring carbonatoms, a substituted or unsubstituted alkylthio group having 1 to 20carbon atoms, a substituted or unsubstituted arylthio group having 6 to30 ring carbon atoms, a group represented by —Si(R₁₀₁)(R₁₀₂)(R₁₀₃), or agroup represented by —Z—R^(a);

the substituents, if present on the naphthalene ring and thephenanthrene ring represented by A and B, may be bonded to each other toform a ring structure;

each of R¹ and R² is independently a hydrogen atom, a fluorine atom, acyano group, a substituted or unsubstituted alkyl group having 1 to 20carbon atoms, a substituted or unsubstituted cycloalkyl group having 3to 20 ring carbon atoms, a substituted or unsubstituted alkoxy grouphaving 1 to 20 carbon atoms, a substituted or unsubstituted fluoroalkylgroup having 1 to 20 carbon atoms, a substituted or unsubstitutedfluoroalkoxy group having 1 to 20 carbon atoms, a substituted orunsubstituted aryloxy group having 6 to 30 ring carbon atoms, asubstituted or unsubstituted alkylthio group having 1 to 20 carbonatoms, a substituted or unsubstituted arylthio group having 6 to 30 ringcarbon atoms, a substituted or unsubstituted aryl group having 6 to 30ring carbon atoms, a substituted or unsubstituted heteroaryl grouphaving 5 to 30 ring carbon atoms, or a group represented by—Si(R₁₀₁)(R₁₀₂)(R₁₀₃);

R¹'s and R²'s, if present, may be the same or different, and R¹'s andR²'s may be bonded to each other to form a ring structure, respectively;

Z is a single bond, a substituted or unsubstituted arylene group having6 to 30 ring carbon atoms, a substituted or unsubstituted heteroarylenegroup having 5 to 30 ring atoms, or a divalent linking group wherein twoto four groups selected from the arylene group and the heteroarylenegroup are linked together;

Zs, if present, may be the same or different;

R^(a) is a group represented by —N(R₁₀₄)(R₁₀₅), a substituted orunsubstituted aryl group having 6 to 30 ring carbon atoms, or asubstituted or unsubstituted heteroaryl group having 5 to 30 ring atoms;

R^(a)'s, if present, may be the same or different;

each of R₁₀₁ to R₁₀₅ is independently a hydrogen atom, a substituted orunsubstituted alkyl group having 1 to 20 carbon atoms, a substituted orunsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, asubstituted or unsubstituted aryl group having 6 to 50 ring carbonatoms, or a substituted or unsubstituted heteroaryl group having 5 to 50ring atoms;

provided that at least one substituent on A and B is a group representedby —Z—R^(a);

two or more groups represented by —Z—R^(a), if present, may be the sameor different; and

each of n1 and n2 is an integer of 0 to 4;

(2) a material for organic electroluminescence devices comprising thecompound described in item (1);(3) an organic electroluminescence device comprising an organic thinfilm layer which comprises one or more layers and is disposed between acathode and an anode, wherein the organic thin film layer comprises alight emitting layer and at least one layer of the organic thin filmlayer comprises the compound described in item (1); and(4) an electronic device comprising the organic electroluminescencedevice described in item (3).

Advantageous Effects of Invention

The organic EL device of the invention has a high emission efficiency atlow voltage and a long lifetime. Since the compound of the invention foruse as a material for organic EL devices has a high carrier mobility,the compound is useful as a host material of a light emitting layer andalso useful as an electron transporting material and a hole transportingmaterial. Particularly, an organic EL device comprising the compound ofthe invention in a light emitting layer as a dopant material has a highemission efficiency at low voltage and a long lifetime.

DESCRIPTION OF EMBODIMENTS

FIG. 1 is a schematic view showing the structure of an example of theorganic EL device in an aspect of the invention.

DESCRIPTION OF EMBODIMENTS

The term of “XX to YY carbon atoms” referred to by “a substituted orunsubstituted group ZZ having XX to YY carbon atoms” used herein is thenumber of carbon atoms of an unsubstituted group ZZ and does not includeany carbon atom in the substituent of a substituted group ZZ.

The term of “XX to YY atoms” referred to by “a substituted orunsubstituted group ZZ having XX to YY atoms” used herein is the numberof atoms of an unsubstituted group ZZ and does not include any atom inthe substituent of a substituted group ZZ.

The number of ring carbon atoms referred to herein means the number ofthe carbon atoms included in the atoms which are members forming thering itself of a compound in which a series of atoms is bonded to form aring (for example, a monocyclic compound, a fused ring compound, across-linked compound, a carbocyclic compound, and a heterocycliccompound). If the ring has a substituent, the carbon atom in thesubstituent is not included in the ring carbon atom. Unless otherwisenoted, the same applies to “the number of ring carbon atoms” describedbelow. For example, a benzene ring has 6 ring carbon atoms, anaphthalene ring has 10 ring carbon atoms, a pyridinyl group has 5 ringcarbon atoms, and a furanyl group has 4 ring carbon atoms. If a benzenering or a naphthalene ring has, for example, an alkyl substituent, thecarbon atom in the alkyl substituent is not counted as the ring carbonatom of the benzene or naphthalene ring. In case of a fluorene ring towhich a fluorene substituent is bonded (inclusive of a spirofluorenering), the carbon atom in the fluorene substituent is not counted as thering carbon atom of the fluorene ring.

The number of ring atoms referred to herein means the number of theatoms which are members forming the ring itself (for example, amonocyclic ring, a fused ring, and a ring assembly) of a compound inwhich a series of atoms is bonded to form the ring (for example, amonocyclic compound, a fused ring compound, a cross-linked compound, acarbocyclic compound, and a heterocyclic compound). The atom not formingthe ring and the atom in a substituent, if the ring is substituted, arenot counted as the ring atom. Unless otherwise noted, the same appliesto “the number of ring atoms” described below. For example, a pyridinering has 6 ring atoms, a quinazoline ring has 10 ring atoms, and a furanring has 5 ring atoms. The hydrogen atom on the ring carbon atom of apyridine ring or a quinazoline ring and the atom in a substituent arenot counted as the ring atom. In case of a fluorene ring to which afluorene substituent is bonded (inclusive of a spirofluorene ring), theatom in the fluorene substituent is not counted as the ring atom of thefluorene ring.

The definition of “hydrogen atom” used herein includes isotopesdifferent in the neutron numbers, i.e., light hydrogen (protium), heavyhydrogen (deuterium), and tritium.

The terms of “heteroaryl group”, “heteroarylene group” and “heterocyclicgroup” used herein means a group having at least one hetero atom as aring atom. The hetero atom is preferably at least one selected from anitrogen atom, an oxygen atom, a sulfur atom, a silicon atom, and aselenium atom.

A “substituted or unsubstituted carbazolyl group” referred to hereinincludes the following carbazolyl groups:

and a substituted carbazolyl group, wherein each of the above carbazolylgroups has an optional substituent.

The optional substituents may be bonded to each other to form a fusedring structure, may include a hetero atom, such as a nitrogen atom, anoxygen atom, a silicon atom, and selenium atom, and may be bonded to anyof 1- to 9-positions. Examples of such substituted carbazolyl groups areshown below.

A “substituted or unsubstituted dibenzofuranyl group” and a “substitutedor unsubstituted dibenzothiophenyl group” referred to herein include thefollowing dibenzofuranyl group and the following dibenzothiophenylgroup:

and a substituted dibenzofuranyl group and a substituteddibenzothiophenyl group, wherein each of the above groups has anoptional substituent.

The optional substituents may be bonded to each other to form a fusedring structure, may include a hetero atom, such as a nitrogen atom, anoxygen atom, a silicon atom, and selenium atom, and may be bonded to anyof 1- to 8-positions.

Examples of such substituted dibenzofuranyl groups and substituteddibenzothiophenyl groups are shown below:

wherein X represents an oxygen atom or a sulfur atom and Y represents anoxygen atom, a sulfur atom, NH, NR^(a) wherein R^(a) represents an alkylgroup or an aryl group, CH₂, or CR^(b) ₂ wherein R^(b) represents analkyl group or an aryl group.

The “substituent” and the optional substituent referred to by“substituted or unsubstituted” used herein is preferably at least oneselected from, but not limited to, the group consisting of an alkylgroup having 1 to 50, preferably 1 to 18, more preferably 1 to 8 carbonatoms; a cycloalkyl group having 3 to 50, preferably 3 to 10, morepreferably 3 to 8, still more preferably 5 or 6 ring carbon atoms; anaryl group having 6 to 50, preferably 6 to 25, more preferably 6 to 18ring carbon atoms; an aralkyl group having 7 to 51, preferably 7 to 30,more preferably 7 to 20 carbon atoms which includes an aryl group having6 to 50, preferably 6 to 25, more preferably 6 to 18 ring carbon atoms;an amino group; a mono- or disubstituted amino group, wherein thesubstituent is selected from an alkyl group having 1 to 50, preferably 1to 18, more preferably 1 to 8 carbon atoms and an aryl group having 6 to50, preferably 6 to 25, more preferably 6 to 18 ring carbon atoms; analkoxy group having an alkyl group having 1 to 50, preferably 1 to 18,more preferably 1 to 8 carbon atoms; an aryloxy group having an arylgroup having 6 to 50, preferably 6 to 25, more preferably 6 to 18 ringcarbon atoms; a mono-, di- or tri-substituted silyl group, wherein thesubstituent is selected from an alkyl group having 1 to 50, preferably 1to 18, more preferably 1 to 8 carbon atoms and an aryl group having 6 to50, preferably 6 to 25, more preferably 6 to 18 ring carbon atoms; aheteroaryl group having 5 to 50, preferably 5 to 24, more preferably 5to 13 ring atoms; a haloalkyl group having 1 to 50, preferably 1 to 18,more preferably 1 to 8 carbon atoms; a halogen atom selected from afluorine atom, a chlorine atom, a bromine atom and an iodine atom; acyano group; a nitro group; a substituted sulfonyl group, wherein thesubstituent is selected from an alkyl group having 1 to 50, preferably 1to 18, more preferably 1 to 8 carbon atoms and an aryl group having 6 to50, preferably 6 to 25, more preferably 6 to 18 ring carbon atoms; adi-substituted phosphoryl group, wherein the substituent is selectedfrom an alkyl group having 1 to 50, preferably 1 to 18, more preferably1 to 8 carbon atoms and an aryl group having 6 to 50, preferably 6 to25, more preferably 6 to 18 ring carbon atoms; an alkylsulfonyloxygroup; an arylsulfonyloxy group; an alkylcarbonyloxy group; anarylcarbonyloxy group; a boron-containing group; a zinc-containinggroup; a tin-containing group; a silicon-containing group; amagnesium-containing group; a lithium-containing group; a hydroxylgroup; an alkyl-substituted or aryl-substituted carbonyl group; acarboxyl group; a vinyl group; a (meth)acryloyl group; an epoxy group;and an oxetanyl group.

The above substituent may further has the substituent mentioned above.The substituents may be bonded to each other to form a ring.

The term of “unsubstituted” referred to by “substituted orunsubstituted” used herein means that no hydrogen atom in the group issubstituted by a substituent.

Of the above substituents, more preferred are a substituted orunsubstituted alkyl group having 1 to 50, preferably 1 to 18, morepreferably 1 to 8 carbon atoms; a substituted or unsubstitutedcycloalkyl group having 3 to 50, preferably 3 to 10, more preferably 3to 8, still more preferably 5 or 6 ring carbon atoms; a substituted orunsubstituted aryl group having 6 to 50, preferably 6 to 25, morepreferably 6 to 18 ring carbon atoms; a mono- or disubstituted aminogroup, wherein the substituent is selected from a substituted orunsubstituted alkyl group having 1 to 50, preferably 1 to 18, morepreferably 1 to 8 carbon atoms and a substituted or unsubstituted arylgroup having 6 to 50, preferably 6 to 25, more preferably 6 to 18 ringcarbon atoms; a substituted or unsubstituted heteroaryl group having 5to 50, preferably 5 to 24, more preferably 5 to 13 ring atoms; a halogenatom; and a cyano group.

A preferred embodiment, for example, for the compounds, the groups, andthe numerical ranges described herein may be combined with any of otherpreferred embodiments, for example, for the compounds, the groups, andthe numerical ranges. A combination of preferred embodiments (inclusiveof more preferred embodiments, still more preferred embodiments, andparticularly preferred embodiments) is a more preferred embodiment.

The compound of the invention is represented by formula (1):

wherein:

each of A and B is a substituted or unsubstituted naphthalene ring or asubstituted or unsubstituted phenanthrene ring;

a substituent on the naphthalene ring or the phenanthrene ring is afluorine atom, a cyano group, a substituted or unsubstituted alkyl grouphaving 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkylgroup having 3 to 20 ring carbon atoms, a substituted or unsubstitutedalkoxy group having 1 to 20 carbon atoms, a substituted or unsubstitutedfluoroalkyl group having 1 to 20 carbon atoms, a substituted orunsubstituted fluoroalkoxy group having 1 to 20 carbon atoms, asubstituted or unsubstituted aryloxy group having 6 to 30 ring carbonatoms, a substituted or unsubstituted alkylthio group having 1 to 20carbon atoms, a substituted or unsubstituted arylthio group having 6 to30 ring carbon atoms, a group represented by —Si(R₁₀₁)(R₁₀₂)(R₁₀₃), or agroup represented by —Z—R^(a);

the substituents, if present on the naphthalene ring and thephenanthrene ring represented by A and B, may be bonded to each other toform a ring structure;

each of R¹ and R² is independently a hydrogen atom, a fluorine atom, acyano group, a substituted or unsubstituted alkyl group having 1 to 20carbon atoms, a substituted or unsubstituted cycloalkyl group having 3to 20 ring carbon atoms, a substituted or unsubstituted alkoxy grouphaving 1 to 20 carbon atoms, a substituted or unsubstituted fluoroalkylgroup having 1 to 20 carbon atoms, a substituted or unsubstitutedfluoroalkoxy group having 1 to 20 carbon atoms, a substituted orunsubstituted aryloxy group having 6 to 30 ring carbon atoms, asubstituted or unsubstituted alkylthio group having 1 to 20 carbonatoms, a substituted or unsubstituted arylthio group having 6 to 30 ringcarbon atoms, a substituted or unsubstituted aryl group having 6 to 30ring carbon atoms, a substituted or unsubstituted heteroaryl grouphaving 5 to 30 ring carbon atoms, or a group represented by—Si(R₁₀₁)(R₁₀₂)(R₁₀₃);

R¹'s and R²'s, if present, may be the same or different, and R¹'s andR²'s may be bonded to each other to form a ring structure, respectively;

Z is a single bond, a substituted or unsubstituted arylene group having6 to 30 ring carbon atoms, a substituted or unsubstituted heteroarylenegroup having 5 to 30 ring atoms, or a divalent linking group wherein twoto four groups selected from the arylene group and the heteroarylenegroup are linked together;

Zs, if present, may be the same or different;

R^(a) is a group represented by —N(R₁₀₄)(R₁₀₅), a substituted orunsubstituted aryl group having 6 to 30 ring carbon atoms, or asubstituted or unsubstituted heteroaryl group having 5 to 30 ring atoms;

R^(a)'s, if present, may be the same or different;

each of R₁₀₁ to R₁₀₅ is independently a hydrogen atom, a substituted orunsubstituted alkyl group having 1 to 20 carbon atoms, a substituted orunsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, asubstituted or unsubstituted aryl group having 6 to 50 ring carbonatoms, or a substituted or unsubstituted heteroaryl group having 5 to 50ring atoms;

provided that at least one substituent on A and B is a group representedby —Z—R^(a);

two or more groups represented by —Z—R^(a), if present, may be the sameor different; and

each of n1 and n2 is an integer of 0 to 4.

In formula (1), examples of the alkyl group having 1 to 20, preferably 1to 10, more preferably 1 to 6 carbon atoms for R¹, R², the substituentof A and B, and R₁₀₁ to R₁₀₅ include a methyl group, an ethyl group, an-propyl group, an isopropyl group, a n-butyl group, an isobutyl group,a s-butyl group, a t-butyl group, a pentyl group (inclusive of isomericgroups), a hexyl group (inclusive of isomeric groups), a heptyl group(inclusive of isomeric groups), an octyl group (inclusive of isomericgroups), a nonyl group (inclusive of isomeric groups), a decyl group(inclusive of isomeric groups), an undecyl group (inclusive of isomericgroups), and a dodecyl group (inclusive of isomeric groups). Preferredare a methyl group, an ethyl group, a n-propyl group, an isopropylgroup, a n-butyl group, an isobutyl group, a s-butyl group, a t-butylgroup, and a pentyl group (inclusive of isomeric groups), with a methylgroup, an ethyl group, a n-propyl group, an isopropyl group, a n-butylgroup, an isobutyl group, a s-butyl group, and a t-butyl group beingmore preferred, and a methyl group, an ethyl group, an isopropyl group,and a t-butyl group being particularly preferred.

Examples of the cycloalkyl group having 3 to 20, preferably 3 to 6, morepreferably 5 or 6 ring carbon atoms for R′, R², the substituent of A andB, and R₁₀₁ to R₁₀₅ include a cyclopropyl group, a cyclobutyl group, acyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctylgroup, and an adamantyl group, with a cyclopentyl group and a cyclohexylgroup being preferred.

Examples of the alkoxy group having 1 to 20, preferably 1 to 10, morepreferably 1 to 6 carbon atoms for R¹, R², and the substituent of A andB include those having an alkyl portion selected from the alkyl grouphaving 1 to 20 carbon atoms mentioned above. Preferred examples of thealkoxy group are those having an alkyl portion selected from thepreferred alkyl group mentioned above.

The fluoroalkyl group having 1 to 20, preferably 1 to 10, morepreferably 1 to 6 carbon atoms for R′, R², and the substituent of A andB is a group derived from the above alkyl group, preferably thepreferred alkyl group mentioned above by substituting a fluorine atomfor a hydrogen atom.

The fluoroalkoxy group having 1 to 20, preferably 1 to 10, morepreferably 1 to 6 carbon atoms for R¹, R², and the substituent of A andB is a group derived from the above alkoxy group, preferably thepreferred alkoxy group mentioned above by substituting a fluorine atomfor a hydrogen atom.

Examples of the aryloxy group having 6 to 30, preferably 6 to 24, morepreferably 6 to 18, still more preferably 6 to 10 ring carbon atoms forR¹, R², and the substituent of A and B include those having an arylportion selected from the aryl group having 6 to 30 ring carbon atomsmentioned below with respect to R¹, R², and R₁₀₁ to R₁₀₅. Preferredexamples of the aryloxy group are those having an aryl portion selectedfrom the preferred aryl group mentioned below.

Examples of the alkylthio group having 1 to 20, preferably 1 to 10, morepreferably 1 to 6 carbon atoms for R¹, R², and the substituent of A andB include those having an alkyl portion selected from the alkyl grouphaving 1 to 20 carbon atoms mentioned above. Preferred examples of thealkoxy group are those having an alkyl portion selected from thepreferred alkyl group mentioned above.

Examples of the arylthio group having 6 to 30, preferably 6 to 24, morepreferably 6 to 18, still more preferably 6 to 10 ring carbon atoms forR¹, R², and the substituent of A and B include those having an arylportion selected from the aryl group having 6 to 30 ring carbon atomsmentioned below with respect to R′, R², and R₁₀₁ to R₁₀₅. Preferredexamples of the arylthio group are those having an aryl portion selectedfrom the preferred aryl group mentioned below.

Examples of the “group represented by —Si(R₁₀₁)(R₁₀₂)(R₁₀₃)” for R¹, R²,and the substituent of A and B include a monoalkylsilyl group, adialkylsilyl group, a trialkylsilyl group, a monoarylsilyl group, adiarylsilyl group, a triarylsilyl group, a monoalkyldiarylsilyl group,and a dialkylmonoarylsilyl group.

The alkyl portion of these substituted silyl groups has preferably 1 to20, more preferably 1 to 10, and still more preferably 1 to 6 carbonatoms. The aryl portion has preferably 6 to 30, more preferably 6 to 24,still more preferably 6 to 18, and particularly preferably 6 to 10 ringcarbon atoms.

Preferred are a trialkylsilyl group and a trialkylsilyl group, with atrimethylsilyl group, a triethylsilyl group, a triisopropylsilyl group,a t-butyldimethylsilyl group, a triphenylsilyl group, and atritolylsilyl group being more preferred.

Examples of the “group represented by —N(R₁₀₄)(R₁₀₅)” for R^(a) informula (1) include a monoalkylamino group, a dialkylamino group, amonoarylamino group, a diarylamino group, a monoheteroarylamino group, adiheteroarylamino group, a monoalkylmonoarylamino group, amonoalkylmonoheteroarylamino group, and a monoarylmonoheteroarylaminogroup. The aryl portion of these substituted amino groups may have asubstituent, for example, an alkyl group having 1 to 20, preferably 1 to10, more preferably 1 to 6 carbon atoms.

The alkyl portion of these substituted amino groups has preferably 1 to20, more preferably 1 to 10, still more preferably 1 to 6 carbon atoms.The aryl portion has preferably 6 to 30, more preferably 6 to 24, stillmore preferably 6 to 18, particularly preferably 6 to 10 ring carbonatoms. The heteroaryl portion has preferably 5 to 30, more preferably 5to 24, still more preferably 5 to 12 ring atoms.

Preferred are a dialkyl amino group, a diarylamino group, adiheteroarylamino group, and a monoarylmonoheteroarylamino group, with adimethylamino group, a diethylamino group, a diisopropylamino group, adiphenylamino group, a bis(alkyl-substituted phenyl)amino group, and abis(aryl-substituted phenyl)amino group being more preferred.

Two or more groups represented by —Si(R₁₀₁)(R₁₀₂)(R₁₀₃), if present informula (1), may be the same or different. Two or more groupsrepresented by —N(R₁₀₄)(R₁₀₅), if present in formula (1), may be thesame or different.

The aryl group having 6 to 30, preferably 6 to 24, more preferably 6 to18, still more preferably 6 to 10 ring carbon atoms for R¹, R², and R₁₀₁to R₁₀₅ may be either a fused ring or a non-fused ring. Examples of thearyl group include a phenyl group, a biphenylyl group, a terphenylylgroup, a naphthyl group, an acenaphthylenyl group, an anthryl group, abenzanthryl group, an aceanthryl group, a phenanthryl group, abenzo[c]phenanthryl group, a phenalenyl group, a fluorenyl group, apicenyl group, a pentaphenyl group, a pyrenyl group, a chrysenyl group,a benzo[g]chrysenyl group, a s-indacenyl group, an as-indacenyl group, afluoranthenyl group, a benzo[k]fluoranthenyl group, a triphenylenylgroup, a benzo[b]triphenylenyl group, and a perylenyl group. Preferredare a phenyl group, a biphenylyl group, a terphenylyl group, a naphthylgroup, an anthryl group, a pyrenyl group, and a fluoranthenyl group,with a phenyl group, a biphenylyl group, and a terphenylyl group beingmore preferred, and a phenyl group being still more preferred.

The heteroaryl group having 5 to 30, preferably 5 to 24, more preferably5 to 12 ring atoms for R¹, R², and R₁₀₁ to R₁₀₅ includes at least one,preferably 1 to 5, more preferably 1 to 4, and still more preferably 1to 3 hetero atoms, which is selected from, for example, a nitrogen atom,a sulfur atom and an oxygen atom and preferably a nitrogen atom and anoxygen atom.

Examples of the heteroaryl group include a pyrrolyl group, a furylgroup, a thienyl group, a pyridyl group, an imidazopyridyl group, apyridazinyl group, a pyrimidinyl group, a pyrazinyl group, a triazinylgroup, an imidazolyl group, an oxazolyl group, a thiazolyl group, apyrazolyl group, an isoxazolyl group, an isothiazolyl group, anoxadiazolyl group, a thiadiazolyl group, a triazolyl group, a tetrazolylgroup, an indolyl group, an isoindolyl group, a benzofuranyl group, anisobenzofuranyl group, a benzothiophenyl group, an isobenzothiophenylgroup, an indolizinyl group, a quinolizinyl group, a quinolyl group, anisoquinolyl group, a cinnolyl group, a phthalazinyl group, aquinazolinyl group, a quinoxalinyl group, a benzimidazolyl group, abenzoxazolyl group, a benzothiazolyl group, an indazolyl group, abenzisoxazolyl group, a benzisothiazolyl group, a dibenzofuranyl group,a dibenzothiophenyl group, a carbazolyl group, a 9-phenylcarbazolylgroup, a phenanthridinyl group, an acridinyl group, a phenanthrolinylgroup, a phenazinyl group, a phenothiazinyl group, a phenoxazinyl group,and a xanthenyl group. Preferred are a pyridyl group, an imidazopyridylgroup, a pyridazinyl group, a pyrimidinyl group, a pyrazinyl group, atriazinyl group, a benzimidazolyl group, a dibenzofuranyl group, adibenzothiophenyl group, a carbazolyl group, a 9-phenylcarbazolyl group,a phenanthrolinyl group, and a quinazolinyl group.

Examples of the arylene group having 6 to 30, preferably 6 to 24, morepreferably 6 to 18, and still more preferably 6 to 10 ring carbon atomsfor Z of formula (1), include divalent groups derived from the arylgroup mentioned above by removing one hydrogen atom. Preferred are aphenylene group, a naphthylene group, an anthrylene group, aphenanthrylene group, a pyrenylene group, and a fluorenylene grouphaving two substituents at 9-position, with a 1,4-phenylene group, a1,3-phenylene group, a 1,2-phenylene group, a 1,4-naphthylene group, a2,6-naphthylene group, a 9,9-dimethyl-2,7-fluorenylene group, and a9,9-diphenyl-2,7-fluorenylene group being more preferred.

Examples of the heteroaryl group having 5 to 30, preferably 5 to 24, andmore preferably 5 to 12 ring atoms for Z include divalent groups derivedfrom the heteroaryl group mentioned above by removing one hydrogen atom.Preferred are a pyridinylene group, a pyrimidinylene group, apyrazinylene group, a pyridazinylene group, a triazinylene group, aphenanthrolinylene group, a dibenzofuranylene group, and adibenzothiophenylene group, with a pyridinylene group, a pyrimidinylenegroup, a triazinylene group, a dibenzofuranylene group, and adibenzothiophenylene group being more preferred. Of the substituentsmentioned above, the substituent of the heteroarylene group ispreferably an aryl group having 6 to 30 ring carbon atoms, morepreferably an aryl group having 6 to 24 ring carbon atoms, still morepreferably an aryl group having 6 to 12 ring carbon atoms, andparticularly preferably a phenyl group.

Z may be a divalent group wherein two to four groups selected from thearylene group and the heteroarylene group are linked together. Examplesof such a divalent group include-arylene group-heteroarylene group-,-heteroarylene group-arylene group-, -arylene group-heteroarylenegroup-arylene group-, -heteroarylene group-arylene group-heteroarylenegroup-, -arylene group-heteroarylene group-arylene group-heteroarylenegroup-, and -heteroarylene group-arylene group-heteroarylenegroup-arylene group-.

Examples and preferred examples of the aryl group and the heteroarylgroup for R^(a) of formula (1) include those mentioned above withrespect to R¹ and R², respectively.

The compound represented by formula (1) is preferably represented by anyof formulae (2-1) to (2-10):

wherein:

R¹, R², n1, and n2 are as defined in formula (1);

each of R¹¹ to R¹⁶, R²¹ to R²⁶, R³¹ to R³⁸, and R⁴¹ to R⁴⁸ isindependently a hydrogen atom, a fluorine atom, a cyano group, asubstituted or unsubstituted alkyl group having 1 to 20 carbon atoms, asubstituted or unsubstituted cycloalkyl group having 3 to 20 ring carbonatoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbonatoms, a substituted or unsubstituted fluoroalkyl group having 1 to 20carbon atoms, a substituted or unsubstituted fluoroalkoxy group having 1to 20 carbon atoms, a substituted or unsubstituted aryloxy group having6 to 30 ring carbon atoms, a substituted or unsubstituted alkylthiogroup having 1 to 20 carbon atoms, a substituted or unsubstitutedarylthio group having 6 to 30 ring carbon atoms, a group represented by—Si(R₁₀₁)(R₁₀₂)(R₁₀₃), or a group represented by —Z—R^(a);

R₁₀₁ to R₁₀₃, Z, and R^(a) are as defined above;

provided that at least one of R¹¹ to R¹⁶ and R²¹ to R²⁶ of each offormulae (2-1), (2-2), (2-3), (2-4), (2-5), and (2-6) is a grouprepresented by —Z—R^(a), at least one of R¹¹ to R¹⁶ and R³¹ to R³⁸ ofeach of formulae (2-7), (2-8), and (2-9) is a group represented by—Z—R^(a), and at least one of R⁴¹ to R⁴⁸ and R³¹ to R³⁸ of formula(2-10) is a group represented by —Z—R^(a);

R¹'s and R²'s, if present, may be the same or different, and R¹'s andR²'s may be bonded to each other to form a ring structure, respectively;and

adjacent two selected from R¹¹ to R¹⁶, R²¹ to R²⁶, R³¹ to R³⁸, and R⁴¹to R⁴⁸ may be bonded to each other to form a ring structure.

In formulae (2-1), (2-2), (2-3), (2-4), (2-5), and (2-6), one of R¹¹ toR¹⁶ is preferably a group represented by —Z—R^(a), or one of R²¹ to R²⁶is preferably a group represented by —Z—R^(a).

In formulae (2-7), (2-8), and (2-9), one of R¹¹ to R¹⁶ is preferably agroup represented by —Z—R^(a), or one of R³¹ to R³⁸ is preferably agroup represented by —Z—R^(a).

In formula (2-10), one of R⁴¹ to R⁴⁸ is preferably a group representedby —Z—R^(a), or one of R³¹ to R³⁸ is preferably a group represented by—Z—R^(a).

In formulae (2-1), (2-2), (2-3), (2-4), (2-5), and (2-6), one of R¹¹ toR¹⁶ is preferably a group represented by —Z—R^(a), and one of R²¹ to R²⁶is preferably a group represented by —Z—R^(a).

In formulae (2-7), (2-8), and (2-9), one of R¹¹ to R¹⁸ is preferably agroup represented by —Z—R^(a), and one of R³¹ to R³⁸ is preferably agroup represented by —Z—R^(a).

In formula (2-10), one of R⁴¹ to R⁴⁸ is preferably a group representedby —Z—R^(a), and one of R³¹ to R³⁸ is preferably a group represented by—Z—R^(a).

Examples and preferred examples of R¹ and R² of formulae (2-1) to (2-10)are the same as those described above with respect to formula (1).

Examples and preferred examples of each group for RH to R¹⁶, R²¹ to R²⁶,R³¹ to R³⁸, and R⁴¹ to R⁴⁸ are the same as those described above withrespect to the substituent of A and B.

The group represented by —Z—R^(a) is preferably represented by any offormulae (a) to (c);

wherein:

each of Z¹ to Z³ is independently a single bond, a substituted orunsubstituted arylene group having 6 to 30 ring carbon atoms, asubstituted or unsubstituted heteroarylene group having 5 to 30 ringatoms, or a divalent linking group wherein two to four groups selectedfrom the arylene group and the heteroarylene group are linked together;

each of L¹ and L² is independently a single bond, a substituted orunsubstituted arylene group having 6 to 30 ring carbon atoms, asubstituted or unsubstituted heteroarylene group having 5 to 30 ringatoms, or a divalent linking group wherein two to four groups selectedfrom the arylene group and the heteroarylene group are linked together;

each of Ar² and Ar³ is independently a substituted or unsubstituted arylgroup having 6 to 30 ring carbon atoms or a substituted or unsubstitutedheteroaryl group having 5 to 30 ring atoms;

HAr is a substituted or unsubstituted heteroaryl group having 5 to 30ring atoms; and

Ar¹ is a substituted or unsubstituted aryl group having 14 to 30 ringcarbon atoms.

Examples and preferred examples of Z¹ to Z³ in formulae (a) to (c) arethe same as those described above with respect to Z in formula (1),respectively. Particularly, in formula (a), Z¹ is preferably a singlebond or an arylene group having 6 to 30 ring carbon atoms and morepreferably a single bond; in formula (b), Z² is preferably a single bondor an arylene group having 6 to 30 ring carbon atoms; and in formula(c), Z³ is preferably a single bond or an arylene group having 6 to 30ring carbon atoms and more preferably an arylene group having 6 to 30ring carbon atoms.

Examples and preferred examples of the arylene group having 6 to 30,preferably 6 to 24, more preferably 6 to 18, and still more preferably 6to 10 ring carbon atoms and the heteroarylene group having 5 to 30,preferably 5 to 24, and more preferably 5 to 12 ring atoms each for L¹and L² in formula (a) are the same as those described above with respectto the arylene group and the heteroarylene group for Z in formula (1),respectively. Examples of the “divalent group wherein two to four groupsselected from the arylene group and the heteroarylene group are linkedtogether” for L¹ and L² include-arylene group-heteroarylene group-,-heteroarylene group-arylene group-, -arylene group-heteroarylenegroup-arylene group-, -heteroarylene group-arylene group-heteroarylenegroup-, -arylene group-heteroarylene group-arylene group-heteroarylenegroup-, and -heteroarylene group-arylene group-heteroarylenegroup-arylene group-.

Examples of the aryl group having 6 to 30, preferably 6 to 20, and morepreferably 6 to 14 ring carbon atoms for Ar² and Ar³ in formula (a)include a phenyl group, a biphenylyl group (2-biphenylyl group,4-biphenylyl group), a terphenylyl group, a naphthyl group, anacenaphthylenyl group, an anthryl group, a benzanthryl group, anaceanthryl group, a phenanthryl group, a benzo[c]phenanthryl group, aphenalenyl group, a fluorenyl group, a picenyl group, a pentaphenylgroup, a pyrenyl group, a chrysenyl group, a benzo[g]chrysenyl group, as-indacenyl group, an as-indacenyl group, a fluoranthenyl group, abenzo[k]fluoranthenyl group, a triphenylenyl group, abenzo[b]triphenylenyl group, and a perylenyl group. In view of theemission efficiency, the device lifetime, and the driving voltage, aphenyl group, a biphenylyl group (2-biphenylyl group, 4-biphenylylgroup), a terphenylyl group, a naphthyl group, and an anthryl group arepreferred; a phenyl group and a biphenylyl group (2-biphenylyl group,4-biphenylyl group) are more preferred; a biphenylyl group (2-biphenylylgroup, 4-biphenylyl group) is still more preferred; and a 4-biphenylylgroup is particularly preferred.

Particularly, in view of the device lifetime, the aryl group preferablyhas a substituent. When the aryl group is a phenyl group, the devicelifetime tends to be largely improved by the presence of a substituent,for example, an alkyl group having 1 to 20 carbon atoms, a cycloalkylgroup having 3 to 20 ring carbon atoms, or an alkoxy group having 1 to30 carbon atoms.

Examples and preferred examples of the heteroaryl group having 5 to 30,preferably 5 to 20, and more preferably 5 to 14 ring atoms for Ar² andAr³ are the same as those described above with respect to the heteroarylgroup for R¹ in formula (1).

In formula (a), each of Ar² and Ar³ is preferably a substituted orunsubstituted aryl group having 6 to 30 ring carbon atoms.

Also preferred is a formula (a), wherein each of L¹ and L² is a singlebond and each of Ar² and Ar³ is independently a substituted orunsubstituted phenyl group, a substituted or unsubstituted naphthylgroup, a substituted or unsubstituted phenanthryl group, a substitutedor unsubstituted fluorenyl group, a substituted or unsubstituteddibenzofuranyl group, or a substituted or unsubstituteddibenzothiophenyl group.

Formula (a) is preferably represented by formula (a′), wherein each ofL¹ and L² is a single bond:

wherein Z¹, Ar², and Ar³ are as defined in formula (a).

Examples and preferred examples of the heteroaryl group having 5 to 30ring atoms for HAr in formula (b) are the same as those described abovewith respect to the heteroaryl group for R¹— and R² in formula (1). HAris more preferably a pyridinyl group, a pyrimidinyl group, a triazinylgroup, a dibenzofuranyl group, or a dibenzothiophenyl group.

Examples of the aryl group having 14 to 30 ring carbon atoms for Ar¹ informula (c) are those having 14 to 30 ring carbon atoms selected fromthe aryl group described above with respect to R¹ and R² in formula (1).Preferred is an aryl group having 14 to 25 ring carbon atoms and morepreferred is an aryl group having 14 to 20 ring carbon atoms. Examplesthereof include an anthryl group, a phenanthryl group, a pyrenyl group,a fluoranthenyl group, and a benzo[k]fluoranthenyl group, with ananthryl group being more preferred. Although not particularly limited,Ar¹ preferably has a substituent, particularly when Z³ is a single bond.The substituent is preferably an aryl group having 6 to 25 ring carbonatoms and more preferably an aryl group having 6 to 12 ring carbonatoms, such as a phenyl group, a naphthyl group, and a biphenylyl group.

—HAr in formula (b) is preferably a group selected from the followinggroups:

wherein:

each R^(c) is independently a fluorine atom, a cyano group, asubstituted or unsubstituted alkyl group having 1 to 20 carbon atoms, asubstituted or unsubstituted cycloalkyl group having 3 to 20 ring carbonatoms, a substituted or unsubstituted aryl group having 6 to 30 ringcarbon atoms, a substituted or unsubstituted aralkyl group having 7 to30 carbon atoms which includes an aryl group having 6 to 30 ring carbonatoms, an amino group, a mono- or dialkylamino group having an alkylgroup having 1 to 20 carbon atoms, a mono- or diarylamino group havingan aryl group having 6 to 30 ring carbon atoms, a substituted orunsubstituted alkoxy group having 1 to 30 carbon atoms, a substituted orunsubstituted aryloxy group having 6 to 30 ring carbon atoms, asubstituted or unsubstituted alkylthio group having 1 to 20 carbonatoms, a substituted or unsubstituted arylthio group having 6 to 30 ringcarbon atoms, a mono-, di-, or tri-substituted silyl group having asubstituent selected from an alkyl group having 1 to 20 carbon atoms andan aryl group having 6 to 30 ring carbon atoms, a substituted orunsubstituted heteroaryl group having 5 to 30 ring atoms, a halogenatom, a cyano group, or a nitro group;

R^(c)s, if present in each group, may be the same or different;

R^(d) is a hydrogen atom, a substituted or unsubstituted alkyl grouphaving 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkylgroup having 3 to 20 ring carbon atoms, a substituted or unsubstitutedaryl group having 6 to 30 ring carbon atoms, or a substituted orunsubstituted heteroaryl group having 5 to 30 ring atoms; and

each p1 is independently an integer of 0 to 4, each p2 is independentlyan integer of 0 to 3, p3 is an integer of 0 to 2, p4 is an integer of 0to 7, and p5 is an integer of 0 to 5.

The free bond “—” in the above groups is bonded to an atom constitutingZ². R^(c) in each group may be bonded to any of the ring carbon atoms.

Examples and preferred examples of each group for R^(c) and R^(d) arethe same as those described above with respect to R¹ and R² in formula(1), respectively.

Preferably, each of p1 to p5 is an integer of 0 to 2.

Of the above, —HAr in formula (b) is preferably the following group:

wherein Re and p3 are as defined above.

In formulae (2-1), (2-2), (2-3), (2-4), (2-5), and (2-6), one of R¹¹ toR¹⁶ is preferably a group represented by any of formulae (a) to (c), orone of R²¹ to R²⁶ is preferably a group represented by any of formulae(a) to (c).

In formulae (2-7), (2-8), and (2-9), one of R¹¹ to R¹⁶ is preferably agroup represented by any of formulae (a) to (c), or one of R³¹ to R³⁸ ispreferably a group represented by any of formulae (a) to (c).

In formula (2-10), one of R⁴¹ to R⁴⁸ is preferably a group representedby any of formulae (a) to (c), or one of R³¹ to R³⁸ is preferably agroup represented by any of formulae (a) to (c).

In formulae (2-1), (2-2), (2-3), (2-4), (2-5), and (2-6), one of R¹¹ toR¹⁶ is preferably a group represented by any of formulae (a) to (c), andone of R²¹ to R²⁶ is preferably a group represented by any of formulae(a) to (c).

In formulae (2-7), (2-8), and (2-9), one of R¹¹ to R¹⁶ is preferably agroup represented by any of formulae (a) to (c), and one of R³¹ to R³⁸is preferably a group represented by any of formulae (a) to (c).

In formula (2-10), one of R⁴¹ to R⁴⁸ is preferably a group representedby any of formulae (a) to (c), and one of R³¹ to R³⁸ is preferably agroup represented by any of formulae (a) to (c).

Examples of the compound of the invention are described below, althoughnot particularly limited thereto.

The compounds of the invention are useful as a material for organic ELdevices.

The production method of the compound of the invention is notparticularly limited, and the compound can be easily produced by usingor modifying a known synthetic reaction while referring to the examplesdescribed below.

Organic EL Device

The organic EL device of the invention will be described below.

The organic EL device comprises an organic thin film layer between acathode and an anode. The organic thin film layer comprises a lightemitting layer and at least one layer of the organic thin film layercomprises the compound of the invention. The organic EL device of theinvention includes one operating at low driving voltage and having along lifetime, and also includes one emitting blue light with a highcolor purity.

Examples of the organic thin film layer which comprises the compound ofthe invention include a hole transporting layer, a light emitting layer,an electron transporting layer, a space layer, and a blocking layer,although not particularly limited thereto.

In view of the emission efficiency and the device lifetime, the compoundof the invention comprising an amino group is preferably used in a lightemitting layer preferably as a dopant material. The compound of theinvention comprising a heteroaryl group, particularly anitrogen-containing heteroaryl group is preferably used in an electrontransporting layer or a blocking layer between a light emitting layerand an electron transporting layer. In view of the driving voltage andthe emission efficiency, the compound of the invention comprising ananthracene skeleton is preferably used in a light emitting layerpreferably as a host material, particularly a fluorescent host material.

The organic EL device of the invention may be any of a fluorescent orphosphorescent single color emitting device, a white-emitting device offluorescent-phosphorescent hybrid type, a simple-type emitting devicehaving a single emission unit, and a tandem emitting device having twoor more emission units. The “emission unit” referred to herein is thesmallest unit for emitting light by the recombination of injected holesand injected electrons, which comprises one or more organic layers,wherein at least one layer is a light emitting layer.

Representative device structures of the simple-type organic EL deviceare shown below:

(1) anode/emission unit/cathode

The emission unit may be a laminated unit comprising two or more layersselected from a phosphorescent light emitting layer and a fluorescentlight emitting layer. A space layer may be disposed between the lightemitting layers to prevent the diffusion of excitons generated in thephosphorescent light emitting layer into the fluorescent light emittinglayer. Representative layered structures of the emission unit are shownbelow:

(a) Hole transporting layer/Light emitting layer (/Electron transportinglayer);(b) Hole transporting layer/First fluorescent emitting layer/Secondfluorescent emitting layer (/Electron transporting layer);(c) Hole transporting layer/Phosphorescent emitting layer/Spacelayer/Fluorescent emitting layer (/Electron transporting layer);(d) Hole transporting layer/First phosphorescent emitting layer/Secondphosphorescent emitting layer/Space layer/Fluorescent emitting layer(/Electron transporting layer);(e) Hole transporting layer/First phosphorescent emitting layer/Spacelayer/Second phosphorescent emitting layer/Space layer/Fluorescentemitting layer (/Electron transporting layer); and(f) Hole transporting layer/Phosphorescent emitting layer/Spacelayer/First fluorescent emitting layer/Second fluorescent emitting layer(/Electron transporting layer).

The emission color of the fluorescent emitting layer and that of thephosphorescent emitting layer may be different. For example, the layeredstructure of the laminated emission layer (d) may be Hole transportinglayer/First phosphorescent emitting layer (red emission)/Secondphosphorescent emitting layer (green emission)/Space layer/Fluorescentemitting layer (blue emission) (/Electron transporting layer).

An electron blocking layer may be disposed between the light emittinglayer and the hole transporting layer or between the light emittinglayer and the space layer, if necessary. Also, a hole blocking layer maybe disposed between the light emitting layer and the electrontransporting layer, if necessary. With such an electron blocking layeror a hole blocking layer, electrons and holes are confined in the lightemitting layer to increase the charge recombination in the lightemitting layer, thereby improving the emission efficiency.

Representative device structure of the tandem-type organic EL device isshown below:

(2) anode/first emission unit/intermediate layer/second emissionunit/cathode.

The layered structure of the first emission unit and the second emissionunit may be selected from those described above with respect to theemission unit.

Generally, the intermediate layer is also called an intermediateelectrode, an intermediate conductive layer, a charge generation layer,an electron withdrawing layer, a connecting layer, or an intermediateinsulating layer. The intermediate layer may be formed by knownmaterials which can supply electrons to the first emission unit andholes to the second emission unit.

A schematic structure of an example of the organic EL device is shown inFIG. 1, wherein the organic EL device 1 comprises a substrate 2, ananode 3, a cathode 4, and an emission unit (organic thin film layer) 10disposed between the anode 3 and the cathode 4. The emission unit 10comprises a light emitting layer 5 which includes at least onefluorescent emitting layer comprising a fluorescent host material and afluorescent dopant material. A hole injecting layer/hole transportinglayer 6 may be disposed between the light emitting layer 5 and the anode3, and an electron injecting layer/electron transporting layer 7 may bedisposed between the light emitting layer 5 and the cathode 4. Anelectron blocking layer may be disposed on the side of anode 3 of thelight emitting layer 5, and a hole blocking layer may be disposed on theside of cathode 4 of the light emitting layer 5. With these blockinglayers, electrons and holes are confined in the light emitting layer 5to increase the exciton generation in the light emitting layer 5.

In the present specification, a host material is referred to as afluorescent host material when combinedly used with a fluorescent dopantmaterial and as a phosphorescent host material when combinedly used witha phosphorescent dopant material. Therefore, the fluorescent hostmaterial and the phosphorescent host material are not distinguished fromeach other merely by the difference in their molecular structures.Namely, in the present invention, the fluorescent host material means amaterial for constituting a fluorescent emitting layer containing afluorescent dopant material and does not mean a material that cannot beutilized as a material for a phosphorescent emitting layer. The sameapplies to the phosphorescent host material.

Substrate

The organic EL device of the invention is formed on a light-transmissivesubstrate. The light-transmissive substrate serves as a support for theorganic EL device and preferably a flat substrate having a transmittanceof 50% or more to 400 to 700 nm visible light. Examples of the substrateinclude a glass plate and a polymer plate. The glass plate may include aplate made of soda-lime glass, barium-strontium-containing glass, leadglass, aluminosilicate glass, borosilicate glass, barium borosilicateglass, or quartz. The polymer plate may include a plate made ofpolycarbonate, acryl, polyethylene terephthalate, polyether sulfide, orpolysulfone.

Anode

The anode of the organic EL device injects holes to the holetransporting layer or the light emitting layer, and an anode having awork function of 4.5 eV or more is effective. Examples of the materialfor anode include indium tin oxide alloy (ITO), tin oxide (NESA), indiumzinc oxide, gold, silver, platinum, and cupper. The anode is formed bymaking the electrode material into a thin film by a method, such as avapor deposition method and a sputtering method. When getting the lightemitted from the light emitting layer through the anode, thetransmittance of anode to visible light is preferably 10% or more. Thesheet resistance of anode is preferably several hundreds Ω/ or less. Thefilm thickness of anode depends upon the kind of material and generally10 nm to 1 μm, preferably 10 to 200 nm.

Cathode

The cathode injects electrons to an electron injecting layer, anelectron transporting layer or a light emitting layer, and formedpreferably by a material having a small work function. Examples of thematerial for cathode include, but not limited to, indium, aluminum,magnesium, a magnesium-indium alloy, a magnesium-aluminum alloy, analuminum-lithium alloy, an aluminum-scandium-lithium alloy, and amagnesium-silver alloy. Like the anode, the cathode is formed by makingthe material into a thin film by a method, such as a vapor depositionmethod and a sputtering method. The emitted light may be taken throughthe cathode, if necessary.

The materials other than the compound of the invention, which are usablein each layer, will be described below.

Light Emitting Layer

The light emitting layer is an organic layer having a light emittingfunction and comprises a host material and a dopant material when adoping system is employed. The major function of the host material is topromote the recombination of electrons and holes and confine excitons inthe light emitting layer. The dopant material causes the excitonsgenerated by recombination to emit light efficiently.

In case of a phosphorescent device, the major function of the hostmaterial is to confine the excitons generated on the dopant in the lightemitting layer.

To control the carrier balance in the light emitting layer, the lightemitting layer may be a double host (host/co-host) layer, for example, alayer in which an electron transporting host material and a holetransporting host material are combinedly used.

The light emitting layer may be a double dopant layer in which two ormore kinds of dopant materials having a high quantum yield arecombinedly used and each dopant emits light with its own color. Forexample, a common light emitting layer formed by co-depositing a host, ared-emitting dopant and a green-emitting dopant emits yellow light.

The light emitting layer may be a double dopant layer in which two ormore kinds of dopant materials having a high quantum yield arecombinedly used and each dopant emits light with its own color. Forexample, a light emitting layer formed by co-depositing a host, ared-emitting dopant and a green-emitting dopant emits yellow light.

The quantum efficiency of the light emitting layer can be improved by alaminate of two or more light emitting layers, because electrons andholes are accumulated in the interface between the light emittinglayers, and therefore, the recombination region is concentrated in theinterface between the light emitting layers.

The easiness of hole injection to the light emitting layer and theeasiness of electron injection to the light emitting layer may bedifferent from each other. Also, the hole transporting ability and theelectron transporting ability each being expressed by mobility of holesand electrons in the light emitting layer may be different from eachother.

The light emitting layer is formed, for example, by a known method, suchas a vapor deposition method, a spin coating method, and LB method. Thelight emitting layer can be formed also by making a solution of abinder, such as resin, and the material for the light emitting layer ina solvent into a thin film by a method, such as a spin coating method.

The light emitting layer is preferably a molecular deposit film. Themolecular deposit film is a thin film formed by depositing a vaporizedmaterial or a film formed by solidifying a material in the state ofsolution or liquid. The molecular deposit film can be distinguished froma thin film formed by LB method (molecular build-up film) by thedifferences in the assembly structures and higher order structures andthe functional difference due to the structural differences.

The thickness of the light emitting layer is preferably 5 to 50 nm, morepreferably 7 to 50 nm, and still more preferably 10 to 50 nm. If 5 nm ormore, the light emitting layer is formed easily. If 50 nm or less, theincrease in the driving voltage is prevented.

Dopant Material

The fluorescent dopant material (fluorescent emitting material) used inthe light emitting layer is a compound which emits light by releasingthe energy of excited singlet state and is not particularly limited aslong as capable of emitting light by releasing the energy of excitedsinglet state. Examples thereof include a fluoranthene derivative, astyrylarylene derivative, a pyrene derivative, an arylacetylenederivative, a fluorene derivative, a boron complex, a perylenederivative, an oxadiazole derivative, an anthracene derivative, astyrylamine derivative, and an arylamine derivative, with an anthracenederivative, a fluoranthene derivative, a styrylamine derivative, anarylamine derivative, a styrylarylene derivative, a pyrene derivative,and a boron complex being preferred, and an anthracene derivative, afluoranthene derivative, a styrylamine derivative, an arylaminederivative, and a boron complex being more preferred.

The content of the fluorescent dopant in the light emitting layer is notparticularly limited and selected according to the use of the device,and preferably 0.1 to 70% by mass, more preferably 1 to 30% by mass, andstill more preferably 1 to 20% by mass, and still further preferably 1to 10% by mass. If being 0.1% by mass or more, the amount of lightemission is sufficient. If being 70% by mass or less, the concentrationquenching is avoided.

Host Material

An anthracene derivative or a polycyclic aromatic compound, preferablyan anthracene derivative is preferably used as the host material for thelight emitting layer.

For example, the following anthracene derivative represented by formula(5) is used as the host material for a blue emitting layer:

wherein:

each of Ar¹¹ and Ar¹² is independently a substituted or unsubstitutedmonocyclic group having 5 to 50 ring atoms or a substituted orunsubstituted fused ring group having 8 to 50 ring atoms; and

each of R¹⁰¹ to R¹⁰⁸ is independently a group selected from a hydrogenatom; a substituted or unsubstituted monocyclic group having 5 to 50,preferably 5 to 30, more preferably 5 to 20, and still more preferably 5to 12 ring atoms; a substituted or unsubstituted fused ring group having8 to 50, preferably 8 to 30, more preferably 8 to 20, and still morepreferably 8 to 14 ring atoms; a group comprising a combination of themonocyclic group and the fused ring group; a substituted orunsubstituted alkyl group having 1 to 50, preferably 1 to 20, morepreferably 1 to 10, and still more preferably 1 to 6 carbon atoms; asubstituted or unsubstituted cycloalkyl group having 3 to 50, preferably3 to 20, more preferably 3 to 10, and still more preferably 5 to 8 ringcarbon atoms; a substituted or unsubstituted alkoxy group having 1 to50, preferably 1 to 20, more preferably 1 to 10, and still morepreferably 1 to 6 carbon atoms; a substituted or unsubstituted aralkylgroup having 7 to 50, preferably 7 to 20, more preferably 7 to 14 carbonatoms; a substituted or unsubstituted aryloxy group having 6 to 50,preferably 6 to 20, more preferably 6 to 12 ring carbon atoms; asubstituted or unsubstituted silyl group; a halogen atom; and a cyanogroup.

In a preferred anthracene derivative, R¹⁰¹ to R¹⁰⁸ are all hydrogenatoms, or one of R¹⁰¹ and R¹⁰⁸, one of R¹⁰⁴ and R¹⁰⁵, both of R¹⁰¹ andR¹⁰⁵, or both of R¹⁰⁸ and R¹⁰⁴ are selected from a monocyclic grouphaving 5 to 50 ring atoms, preferably a phenyl group, a biphenylylgroup, and a terphenylyl group; a substituted or unsubstituted alkylgroup having 1 to 50 carbon atoms, preferably a methyl group, an ethylgroup, a n-propyl group, an isopropyl group, a n-butyl group, anisobutyl group, a s-butyl group, and a t-butyl group; and a substitutedsilyl group, preferably a trimethylsilyl group. An anthracene derivativewherein R¹⁰¹ to R¹⁰⁸ are all hydrogen atoms is more preferred.

The monocyclic group of formula (5) is a group composed of only anon-fused ring structure.

Examples of the monocyclic group having 5 to 50 ring atoms include anaromatic group, such as a phenyl group, a biphenylyl group, aterphenylyl group, and a quaterphenylyl group; and a heterocyclic group,such as a pyridyl group, a pyrazyl group, a pyrimidyl group, a triazinylgroup, a furyl group, and a thienyl group, with a phenyl group, abiphenylyl group, and a terphenylyl group being preferred.

The fused ring group of formula (5) is a group wherein two or more ringstructures are fused to each other.

Examples of the fused ring group having 8 to 50 ring atoms include afused aromatic ring group, such as a naphthyl group, a phenanthrylgroup, an anthryl group, a chrysenyl group, a benzanthryl group, abenzophenanthryl group, a triphenylenyl group, a benzochrysenyl group,an indenyl group, a fluorenyl group, a 9, 9-dimethylfluorenyl group, abenzofluorenyl group, a dibenzofluorenyl group, a fluoranthenyl group,and a benzofluoranthenyl group; and a fused heterocyclic group, such asa benzofuranyl group, a benzothiophenyl group, an indolyl group, adibenzofuranyl group, a dibenzothiophenyl group, a carbazolyl group, aquinolyl group, and a phenanthrolinyl group; with a naphthyl group, aphenanthryl group, an anthryl group, a 9, 9-dimethylfluorenyl group, afluoranthenyl group, a benzanthryl group, a dibenzothiophenyl group, adibenzofuranyl group, and a carbazolyl group being preferred.

The substituent of Ar¹¹ and Ar¹² is preferably selected from themonocyclic groups and the fused ring groups mentioned above.

In formula (5), examples of the alkyl group, the cycloalkyl group, thealkoxy group, the alkyl portion and the aryl portion of the aralkylgroup, the aryloxy group, and the substituted silyl group (an alkylsilylgroup and an arylsilyl group) are the same as those mentioned above withrespect to R¹ and R² of formula (1). The halogen atom includes afluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

In formula (5), preferably R¹⁰¹ to R¹⁰⁸ are all hydrogen atoms, or oneof R¹⁰¹ and R¹⁰⁸, one of R¹⁰⁴ and R¹⁰⁵, both of R¹⁰¹ and R¹⁰⁵, or bothof R¹⁰⁸ and R¹⁰⁴ are selected from a monocyclic group having 5 to 50ring atoms, preferably a phenyl group, a biphenylyl group, and aterphenylyl group; a substituted or unsubstituted alkyl group having 1to 50 carbon atoms, preferably a methyl group, an ethyl group, an-propyl group, an isopropyl group, a n-butyl group, an isobutyl group,a s-butyl group, and a t-butyl group; and a substituted silyl group,preferably a trimethylsilyl group. More preferably, R¹⁰¹ to R¹⁰⁸ are allhydrogen atoms.

The anthracene derivative represented by formula (5) is preferably anyof the following anthracene derivatives (A), (B) and (C), which areselected according to the constitution and the required properties ofthe organic EL device in which the anthracene derivative is to be used.

Anthracene Derivative (A)

The anthracene derivative (A) is represented by formula (5) wherein Ar¹¹and Ar¹² independently represent a substituted or unsubstituted fusedring group having 8 to 50 ring atoms and may be the same or different.

An anthracene derivative of formula (5) wherein Ar¹¹ and Ar¹² aredifferent substituted or unsubstituted fused ring groups (inclusive ofthe difference in the positions connecting to the anthracene ring) isparticularly preferable. Preferred examples of the fused ring are asdescribed above, with a naphthyl group, a phenanthryl group, abenzanthryl group, a 9, 9-dimethylfluorenyl group, and a dibenzofuranylgroup being more preferred.

Anthracene Derivative (B)

The anthracene derivative (B) is represented by formula (5) wherein oneof Ar¹¹ and Ar¹² is a substituted or unsubstituted monocyclic grouphaving 5 to 50 ring atoms and the other is a substituted orunsubstituted fused ring group having 8 to 50 ring atoms.

In a preferred anthracene derivative (B), Ar¹² is a naphthyl group, aphenanthryl group, a benzanthryl group, a 9, 9-dimethylfluorenyl group,or a dibenzofuranyl group; and Ar¹¹ is an unsubstituted phenyl group ora substituted phenyl group having a substituent selected from themonocyclic group and the fused ring group, for example, a phenyl group,a biphenyl group, a naphthyl group, a phenanthryl group, a 9,9-dimethylfluorenyl group, and a dibenzofuranyl group

In another preferred anthracene derivative (B), Ar¹² is a substituted orunsubstituted fused ring group having 8 to 50 ring atoms and Ar¹¹ is anunsubstituted phenyl group. The fused ring group is particularlypreferably a phenanthryl group, a 9, 9-dimethylfluorenyl group, adibenzofuranyl group, or a benzanthryl group.

Anthracene Derivative (C)

The anthracene derivative (C) is represented by formula (5) wherein Ar¹¹and Ar¹² each independently represent a substituted or unsubstitutedmonocyclic group having 5 to 50 ring atoms.

In a preferred anthracene derivative (C), both of Ar¹¹ and Ar¹² aresubstituted or unsubstituted phenyl groups.

In a more preferred anthracene derivative (C), Ar¹¹ is an unsubstitutedphenyl group and Ar¹² is a phenyl group having a substituent selectedfrom the monocyclic group and the fused ring group; or Ar¹¹ and Ar¹²each independently represent a phenyl group having a substituentselected from the monocyclic group and the fused ring group.

Examples of the monocyclic substituent and the fused ring substituentare as described above. Preferably, the monocyclic substituent is aphenyl group or a biphenyl group, and the fused ring substituent is anaphthyl group, a phenanthryl group, a 9, 9-dimethylfluorenyl group, adibenzofuranyl group, or a benzanthryl group.

Examples of the anthracene derivative represented by formula (5) aredescribed below.

Electron-Donating Dopant Material

The organic EL device of the invention preferably comprises anelectron-donating dopant material in the interfacial region between thecathode and the light emission unit. With such a construction, theorganic EL device has an improved luminance and an elongated lifetime.The electron-donating dopant material is a metal having a work functionof 3.8 eV or less or a compound containing such a metal. Examplesthereof include at least one selected from an alkali metal, an alkalimetal complex, an alkali metal compound, an alkaline earth metal, analkaline earth metal complex, an alkaline earth metal compound, a rareearth metal, a rare earth metal complex, and a rare earth metalcompound.

Examples of the alkali metal include Na (work function: 2.36 eV), K(work function: 2.28 eV), Rb (work function: 2.16 eV), and Cs (workfunction: 1.95 eV), with those having a work function of 2.9 eV or lessbeing particularly preferred. Examples of the alkaline earth metalinclude Ca (work function: 2.9 eV), Sr (work function: 2.0 to 2.5 eV),and Ba (work function: 2.52 eV), with those having a work function of2.9 eV or less being particularly preferred. Examples of the rare earthmetal include Sc, Y, Ce, Tb, and Yb, with those having a work functionof 2.9 eV or less being particularly preferred.

Examples of the alkali metal compound include alkali oxide, such asLi₂O, Cs₂O, K₂O, and alkali halide, such as LiF, NaF, CsF, and KF, withLiF, Li₂O, and NaF being preferred. Examples of the alkaline earth metalcompound include BaO, SrO, CaO, and a mixture thereof, such asBa_(x)Sr_(1-x)O (0<x<1) and Ba_(x)CA¹ _(-x)O (0<x<1), with BaO, SrO, andCaO being preferred. Examples of the rare earth metal compound includeYbF₃, ScF₃, ScO₃, Y₂O₃, Ce₂O₃, GdF₃, and TbF₃, with YbF₃, ScF₃, and TbF₃being preferred.

Examples of the alkali metal complex, alkaline earth metal complex, andrare earth metal are not particularly limited as long as containing atleast one metal ion selected from alkali metal ions, alkaline earthmetal ions, and rare earth metal ions, respectively. Examples of theligand include quinolinol, benzoquinolinol, acridinol, phenanthridinol,hydroxyphenyloxazole, hydroxyphenylthiazole, hydroxydiaryloxadiazole,hydroxydiarylthiadiazole, hydroxyphenylpyridine,hydroxyphenylbenzimidazole, hydroxybenzotriazole, hydroxyfulborane,bipyridyl, phenanthroline, phthalocyanine, porphyrin, cyclopentadiene,β-diketones, azomethines, and a derivative thereof.

The electron-donating dopant material is added to the interfacial regionpreferably into a form of layer or island. The electron-donating dopantmaterial is added preferably by co-depositing the electron-donatingdopant material with the organic compound (light emitting material,electron injecting material, etc.) for forming the interfacial region bya resistance heating deposition method, thereby dispersing theelectron-donating dopant material into the organic material. Thedisperse concentration expressed by the molar ratio of the organicmaterial and the electron-donating dopant material is 100:1 to 1:100.

When the electron-donating dopant material is formed into a form oflayer, a light emitting material or an electron injecting material ismade into a layer to form an interfacial organic layer, and then, theelectron-donating dopant material alone is deposited by a resistanceheating deposition method into a layer having a thickness preferably 0.1to 15 nm. When the electron-donating dopant material is formed into aform of island, a light emitting material or an electron injectingmaterial is made into a form of island to form an interfacial organiclayer, and then, the electron-donating dopant material alone isdeposited by a resistance heating deposition method into a form ofisland having a thickness preferably 0.05 to 1 nm.

The molar ratio of the main component and the electron-donating dopantmaterial in the organic EL device is preferably 5:1 to 1:5.

Electron Transporting Layer

The electron transporting layer is an organic layer disposed between thelight emitting layer and the cathode and transports electrons from thecathode to the light emitting layer. If two or more electrontransporting layers are provided, the organic layer closer to thecathode may be called an electron injecting layer in some cases. Theelectron injecting layer injects electrons from the cathode to theorganic layer unit efficiently.

An aromatic heterocyclic compound having one or more heteroatoms in itsmolecule is preferably used as the electron transporting material forthe electron transporting layer, with a nitrogen-containing ringderivative being particularly preferred. The nitrogen-containing ringderivative is preferably an aromatic ring compound having anitrogen-containing 6- or 5-membered ring or a fused aromatic ringcompound having a nitrogen-containing 6- or 5-membered ring.

The nitrogen-containing ring derivative is preferably, for example, achelate metal complex having a nitrogen-containing ring represented byformula (A):

In formula (A), each of R² to R⁷ is independently a hydrogen atom, ahalogen atom, a hydroxyl group, an amino group, a hydrocarbon grouphaving 1 to 40, preferably 1 to 20, more preferably 1 to 10, and stillmore preferably 1 to 6 carbon atoms, an alkoxy group having 1 to 40,preferably 1 to 20, more preferably 1 to 10, and still more preferably 1to 6 carbon atoms, an aryloxy group having 6 to 40, preferably 6 to 20,more preferably 6 to 12 ring carbon atoms, an alkoxycarbonyl grouphaving 2 to 40, preferably 2 to 20, more preferably 2 to 10, and stillmore preferably 2 to 5 carbon atoms, or an aromatic heterocyclic grouphaving 9 to 40, preferably 9 to 30, more preferably 9 to 20 ring atoms,each optionally having a substituent.

M is aluminum (Al), gallium (Ga), or indium (In), with In beingpreferred.

L is a group represented by formula (A′) or (A″):

each of R⁸ to R¹² in formula (A′) is independently a hydrogen atom or asubstituted or unsubstituted hydrocarbon group having 1 to 40,preferably 1 to 20, more preferably 1 to 10, and still more preferably 1to 6 carbon atoms, and adjacent groups may form a ring structure; andR¹³ to R²⁷ in formula (A″) each independently represent a hydrogen atomor a substituted or unsubstituted hydrocarbon group having 1 to 40,preferably 1 to 20, more preferably 1 to 10, and still more preferably 1to 6 carbon atoms, and adjacent groups may form a ring structure.

Examples of the hydrocarbon group having 1 to 40 carbon atomsrepresented by R⁸ to R¹² of formula (A′) and R¹³ to R²⁷ of formula (A″)are the same as mentioned above with respect to R² to R⁷ of formula (A).

Examples of the divalent group to be formed when adjacent groupsselected from R⁸ to R¹² and R¹³ to R²⁷ form a ring structure include atetramethylene group, a pentamethylene group, a hexamethylene group, adiphenylmethane-2,2′-diyl group, a diphenylethane-3,3′-diyl group, and adiphenylpropane-4,4′diyl group.

The electron transporting compound for the electron transporting layeris preferably a metal complex, such as 8-hydroxyquinoline or itsderivative, an oxadiazole derivative, and a nitrogen-containingheterocyclic derivative.

Electron transporting compounds which have a good thin film-formingproperty are preferably used. Examples of the electron transportingcompound are shown below.

Examples of the nitrogen-containing heterocyclic derivative for use asthe electron transporting compound include a nitrogen-containingcompound other than a metal complex, for example, a compound having thenitrogen-containing heterocyclic group represented by any of thefollowing formulae is preferably used.

wherein, R is an aromatic hydrocarbon group or a fused aromatichydrocarbon group each having 6 to 40 carbon atoms, an aromaticheterocyclic group or a fused aromatic heterocyclic group each having 3to 40 carbon atoms, an alkyl group having 1 to 20 carbon atoms, or analkoxy group having 1 to 20 carbon atoms; n is an integer of 0 to 5; andwhen n is an integer of 2 or more, R groups may by the same ordifferent.

The electron transporting layer of the organic EL of the inventionparticularly preferably comprises at least one of thenitrogen-containing heterocyclic derivatives represented by formulae(60) to (62);

wherein:

each of Z¹¹, Z¹², and Z¹³ is independently a nitrogen atom or a carbonatom;

each of R^(A) and R^(B) is independently a substituted or unsubstitutedaryl group having 6 to 50, preferably 6 to 30, more preferably 6 to 20,and still more preferably 6 to 12 ring carbon atoms, a substituted orunsubstituted heterocyclic group having 5 to 50, preferably 5 to 30,more preferably 5 to 20, and still more preferably 5 to 12 ring atoms, asubstituted or unsubstituted alkyl group having 1 to 20, preferably 1 to10, and more preferably 1 to 6 carbon atoms, a substituted orunsubstituted haloalkyl group having 1 to 20, preferably 1 to 10, andmore preferably 1 to 6 carbon atoms, or a substituted or unsubstitutedalkoxyl group having 1 to 20, preferably 1 to 10, and more preferably 1to 6 carbon atoms;

n is an integer of 0 to 5, when n is an integer of 2 or more, groupsR^(A) may be the same or different from each other, and adjacent twogroups R^(A) may bond to each other to form a substituted orunsubstituted hydrocarbon ring;

Ar¹¹ represents a substituted or unsubstituted aryl group having 6 to50, preferably 6 to 30, more preferably 6 to 20, and still morepreferably 6 to 12 ring carbon atoms or a substituted or unsubstitutedheterocyclic group having 5 to 50, preferably 5 to 30, more preferably 5to 20, and still more preferably 5 to 12 ring atoms;

Ar¹² represents a hydrogen atom, a substituted or unsubstituted alkylgroup having 1 to 20, preferably 1 to 10, and more preferably 1 to 6carbon atoms, a substituted or unsubstituted haloalkyl group having 1 to20, preferably 1 to 10, and more preferably 1 to 6 carbon atoms, asubstituted or unsubstituted alkoxyl group having 1 to 20, preferably 1to 10, and more preferably 1 to 6 carbon atoms, a substituted orunsubstituted aryl group having 6 to 50, preferably 6 to 30, morepreferably 6 to 20, and still more preferably 6 to 12 ring carbon atoms,or a substituted or unsubstituted heterocyclic group having 5 to 50,preferably 5 to 30, more preferably 5 to 20, and still more preferably 5to 12 ring atoms;

provided that one of Ar¹¹ and Ar¹² is a substituted or unsubstitutedfused aromatic hydrocarbon group having 10 to 50, preferably 10 to 30,more preferably 10 to 20, and still more preferably 10 to 14 ring carbonatoms or a substituted or unsubstituted fused aromatic heterocyclicgroup having 9 to 50, preferably 9 to 30, more preferably 9 to 20, andstill more preferably 9 to 14 ring atoms;

Ar¹³ represents a substituted or unsubstituted arylene group having 6 to50, preferably 6 to 30, more preferably 6 to 20, and still morepreferably 6 to 12 ring carbon atoms or a substituted or unsubstitutedheteroarylene group having 5 to 50, preferably 5 to 30, more preferably5 to 20, and still more preferably 5 to 12 ring atoms; and

each of L¹, L², and L³ is independently a single bond, a substituted orunsubstituted arylene group having 6 to 50, preferably 6 to 30, morepreferably 6 to 20, and still more preferably 6 to 12 ring carbon atomsor a substituted or unsubstituted divalent fused aromatic heterocyclicgroup having 9 to 50, preferably 9 to 30, more preferably 9 to 20, andstill more preferably 9 to 14 ring atoms.

Examples of the nitrogen-containing heterocyclic derivatives representedby formulae (60) to (62) are shown below.

The electron transporting layer of the organic EL device of theinvention may be a two-layered structure comprising a first electrontransporting layer (anode side) and a second electron transporting layer(cathode side).

The thickness of the electron transporting layer is preferably 1 to 100nm, although not particularly limited thereto. If the electrontransporting layer is a two-layered structure comprising a firstelectron transporting layer (anode side) and a second electrontransporting layer (cathode side), the thickness of the first electrontransporting layer is preferably 5 to 60 nm and more preferably 10 to 40nm, and the thickness of the second electron transporting layer ispreferably 1 to 20 nm and more preferably 1 to 10 nm.

The electron injecting layer which may be formed adjacent to theelectron transporting layer preferably includes an inorganic compound,such as an insulating material and a semiconductor, in addition to thenitrogen-containing ring derivative. The insulating material orsemiconductor constituting the electron injecting layer effectivelyprevents the leak of electric current to enhance the electron injectingproperties.

The insulating material is preferably at least one metal compoundselected from the group consisting of an alkali metal chalcogenide, analkaline earth metal chalcogenide, an alkali metal halide, and analkaline earth metal halide. The alkali metal chalcogenide, etc.incorporated into the electron injecting layer further enhances theelectron injecting properties. Preferred examples of the alkali metalchalcogenides include L¹ ₂O, K₂O, Na₂S, Na₂Se, and Na₂O, and preferredexamples of the alkaline earth metal chalcogenides include CaO, BaO,SrO, BeO, BaS, and CaSe. Preferred examples of the alkali metal halidesinclude LiF, NaF, KF, LiCl, KCl, and NaCl. Examples of the alkalineearth metal halides include fluorides such as CaF₂, BaF₂, SrF₂, MgF₂,and BeF₂ and halides other than fluorides.

Examples of the semiconductor may include an oxide, a nitride or anoxynitride each containing at least one element selected from the groupconsisting of Ba, Ca, Sr, Yb, Al, Ga, In, Li, Na, Cd, Mg, Si, Ta, Sb andZn. The semiconductor may be used singly or in combination of two ormore. The inorganic compound forming the electron injecting layerpreferably forms a microcrystalline or amorphous insulating thin film.When the electron injecting layer is formed from such an insulating thinfilm, the thin film is made more uniform to decrease the pixel defectssuch as dark spots. Examples of such an inorganic compound include analkali metal chalcogenide, an alkaline earth metal chalcogenide, analkali metal halide, and an alkaline earth metal halide.

The thickness of the layer including the insulating material or thesemiconductor is preferably about 0.1 to 15 nm. The electron injectinglayer may include the electron-donating dopant material described above.

Hole Transporting Layer

The hole transporting layer is an organic layer formed between the lightemitting layer and the anode and has a function of transporting holesfrom the anode to the light emitting layer. When the hole transportinglayer is formed by two or more layers, the layer closer to the anode maybe defined as the hole injecting layer in some cases. The hole injectinglayer has a function of efficiently injecting holes from the anode tothe organic layer unit.

An aromatic amine compound, for example, an aromatic amine derivativerepresented by formula (I), is preferably used as the material forforming the hole transporting layer:

wherein:

each of Ar¹ to Ar⁴ is a substituted or unsubstituted aromatichydrocarbon group having 6 to 50, preferably 6 to 30, more preferably 6to 20, and still more preferably 6 to 12 ring carbon atoms; asubstituted or unsubstituted fused aromatic hydrocarbon group having 6to 50, preferably 6 to 30, more preferably 6 to 20, and still morepreferably 6 to 12 ring carbon atoms; a substituted or unsubstitutedaromatic heterocyclic group having 5 to 50, preferably 5 to 30, morepreferably 5 to 20, and still more preferably 5 to 12 ring atoms; asubstituted or unsubstituted fused aromatic heterocyclic group having 5to 50, preferably 5 to 30, more preferably 5 to 20, and still morepreferably 5 to 12 ring atoms; or a group wherein the aromatichydrocarbon group or the fused aromatic hydrocarbon group is bonded tothe aromatic heterocyclic group or the fused aromatic heterocyclicgroup;

Ar¹ and Ar², or Ar³ and Ar⁴ may form a ring; and

L represents a substituted or unsubstituted aromatic hydrocarbon grouphaving 6 to 50, preferably 6 to 30, more preferably 6 to 20, and stillmore preferably 6 to 12 ring carbon atoms; a substituted orunsubstituted fused aromatic hydrocarbon group having 6 to 50,preferably 6 to 30, more preferably 6 to 20, and still more preferably 6to 12 ring carbon atoms; a substituted or unsubstituted aromaticheterocyclic group having 5 to 50, preferably 5 to 30, more preferably 5to 20, and still more preferably 5 to 12 ring atoms; or a fused aromaticheterocyclic group having 5 to 50, preferably 5 to 30, more preferably 5to 20, and still more preferably 5 to 12 ring atoms.

Examples of the compound represented by formula (I) are shown below.

The aromatic amine represented by formula (II) is also preferably usedas the material for forming the hole transporting layer:

wherein Ar¹ to Ar³ are as defined above with respect to Ar¹ to Ar⁴ offormula (I). Examples of the compounds represented by formula (II) areshown below, although not limited thereto.

The hole transporting layer of the organic EL device of the inventionmay be made into a two-layered structure comprising a first holetransporting layer (anode side) and a second hole transporting layer(cathode side).

The thickness of the hole transporting layer is preferably 10 to 200 nm,although not particularly limited thereto. If the hole transportinglayer is a two-layered structure comprising a first hole transportinglayer (anode side) and a second hole transporting layer (cathode side),the thickness of the first hole transporting layer is preferably 50 to150 nm and more preferably 50 to 110 nm, the thickness of the secondhole transporting layer is preferably 5 to 50 nm and more preferably 5to 30 nm.

The organic EL device of the invention may have a layer comprising anacceptor material which is attached to the anode side of the holetransporting layer or the first hole transporting layer. With such alayer, it is expected that the driving voltage is lowered and theproduction cost is reduced.

The acceptor material is preferably a compound represented by thefollowing formula:

The thickness of the layer comprising the acceptor material ispreferably 5 to 20 nm, although not particularly limited thereto.

N/P Doping

The carrier injecting properties of the hole transporting layer and theelectron transporting layer can be controlled by, as described in JP3695714B, the doping (n) with a donor material or the doping (p) with anacceptor material.

A typical example of the n-doping is an electron transporting materialdoped with a metal, such as Li and Cs, and a typical example of thep-doping is a hole transporting material doped with an acceptormaterial, such as F₄TCNQ.

Space Layer

For example, when a fluorescent emitting layer and a phosphorescentemitting layer are laminated, a space layer may be disposed between thefluorescent emitting layer and the phosphorescent emitting layer toprevent the diffusion of excitons generated in the phosphorescentemitting layer into the fluorescent emitting layer or to control thecarrier balance. The space layer may be disposed between phosphorescentemitting layers.

Since the space layer is disposed between light emitting layers, amaterial combining the electron transporting ability and the holetransporting ability is preferably used for forming the space layer. Toprevent the diffusion of triplet energy in the adjacent phosphorescentemitting layer, the triplet energy of the material for the space layeris preferably 2.6 eV or more. The materials described above with respectto the hole transporting layer are usable as the material for the spacelayer.

Blocking Layer

The organic EL device of the invention preferably comprises a blockinglayer, such as an electron blocking layer, a hole blocking layer, and atriplet blocking layer, which is disposed adjacent to the light emittinglayer. The electron blocking layer is a layer which prevents thediffusion of electrons from a light emitting layer to a holetransporting layer and formed between the light emitting layer and thehole transporting layer. The hole blocking layer is a layer whichprevents the diffusion of holes from a light emitting layer to anelectron transporting layer and formed between the light emitting layerand the electron transporting layer.

The triplet blocking layer prevents the diffusion of triplet excitonsgenerated in the light emitting layer to adjacent layers and confinesthe triplet excitons in the light emitting layer, thereby preventing thedeactivation of energy on molecules other than the emitting dopant oftriplet excitons, for example, on molecules in the electron transportinglayer.

The electron mobility of the electron injecting layer is preferably 10⁻⁶cm²/Vs or more at an electric field strength in a range of 0.04 to 0.5MV/cm. Within the above range, the injection of electrons from thecathode to the electron transporting layer is promoted and the injectionof electrons to the adjacent blocking layer and light emitting layer isalso promoted, thereby enabling to drive a device at lower voltage.

Electronic Device

Since the organic EL device comprising the compound of the invention isfurther improved in the emission efficiency, the organic EL device isusable in an electronic device, for example, as display parts, such asorganic EL panel module, display devices of television sets, mobilephones, personal computer, etc., and light emitting sources of lightingequipment and vehicle lighting equipment.

EXAMPLES

The present invention will be described in more detail with reference tothe examples. However, it should be noted that the scope of theinvention is not limited to the following examples.

Synthesis Example 1 (Synthesis of Aromatic Heterocyclic Derivative (E1))(1) Synthesis of Intermediate 1

Under argon atmosphere, a solution of 1-bromonaphtharene (110.5 g, 533.6mmol) in tetrahydrofuran (1 L) was added to magnesium (14.0 g, 576.0mmol) dropwise. After stirring the resultant solution at 25° C. for 1 h,a tetrahydrofuran solution (100 mL) of 1-naphthoaldehyde (113.1 g, 724.2mmol) was added dropwise at room temperature and the resultant solutionwas stirred at 20° C. for 1.5 h. After the reaction, a 2 N hydrochloricacid (300 mL) was added and the stirring was continued for 30 min. Then,the solution was extracted with toluene (800 mL). The collected organiclayer was concentrated and the obtained solid was washed with ethanol toobtain a white solid (91.3 g), which was identified as the followingintermediate 1 by FD-MS analysis (Field Desorption Mass Spectrometry)(m/e=284 for molecular weight of 284.35). The yield was 60%.

(2) Synthesis of Intermediate 2

Into phosphoric acid (1.65 L) heated to 150° C., the intermediate 1(87.8 g, 308.8 mmol) was added little by little, and the resultantmixture was stirred for 40 h under heating. After the reaction, thereaction liquid was left to stand for cooling to room temperature,poured into iced water (1 L), and then extracted with toluene. Theorganic layer was concentrated and the obtained solid was purified bysilica gel column chromatography to obtain a white solid (36.9 g), whichwas identified as the following intermediate 2 by FD-MS analysis(m/e=266 for molecular weight of 266.34). The yield was 45%.

(3) Synthesis of Intermediate 3

Into a solution of intermediate 2 (15.0 g, 56.3 mmol) in pyridine (1 L),a 40% methanol solution (60 mL) of benzyltrimethylammonium hydroxide(Triton-B) was added dropwise at room temperature. After stirring for 30min, the resultant solution was added slowly to concentratedhydrochloric acid under cooling with ice and then extracted withdichloromethane. The organic layer was concentrated and the obtainedsolid was purified by silica gel column chromatography to obtain a brownsolid (9.3 g), which was identified as the following intermediate 3 byFD-MS analysis (m/e=280 for molecular weight of 280.32). The yield was59%.

(4) Synthesis of Intermediate 4

Under argon atmosphere, a 0.5 M diethyl ether solution (60.8 mL, 30.4mmol) of 2-biphenylmagnesium bromide was cooled to −20° C. Theintermediate 3 (6.0 g, 21.4 mmol) was added to the solution little bylittle, while allowing the temperature to gradually rise to roomtemperature, and the solution was stirred at room temperature for 5 h.Then, the stirring was further continued for 5 h by refluxing underheating. After the reaction, the solution was cooled to roomtemperature. After adding a saturated aqueous solution of ammoniumchloride, the solution was extracted with ethyl acetate. The organiclayer was concentrated and the obtained solid was purified by silica gelcolumn chromatography to obtain a white solid (6.5 g), which wasidentified as the following intermediate 4 by FD-MS analysis (m/e=434for molecular weight of 434.53). The yield was 58%.

(5) Synthesis of Intermediate 5

Acetic acid (500 mL) was added to the intermediate 4 (5.0 g, 11.5 mmol),to which concentrated hydrochloric acid (10 mL) was added dropwise whilestirring at 140° C. under heating. The reaction was allowed to proceedat 140° C. for 8 h. After the reaction, the reaction liquid was left tostand for cooling to room temperature and the precipitated solid wascollected by filtration. The obtained solid was washed with ethanol toobtain a white solid (2.8 g), which was identified as the followingintermediate 5 by FD-MS analysis (m/e=416 for molecular weight of416.51). The yield was 58%.

(6) Synthesis of Intermediate 6

Under argon atmosphere, into a solution of the intermediate 5 (2.8 g,6.7 mmol) in dichloromethane (22 mL), a solution of bromine (0.90 g, 5.6mmol) in dichloromethane (18 mL) was added dropwise under cooling withice. The reaction was allowed to proceed overnight. After adding anaqueous solution of sodium hydrogen carbonate, the reaction mixture wasextracted with dichloromethane and the solvent was evaporated off underreduced pressure. The obtained residue was purified by recrystallizationto obtain a white solid (1.33 g), which was identified as the followingintermediate 6 by FD-MS analysis (m/e=495 for molecular weight of495.41). The yield was 40%.

(7) Synthesis of Intermediate 7

Under argon atmosphere, into a solution of the intermediate 6 (0.99 g,2.0 mmol) in anhydrous THF (20 mL), a 1.6 M hexane solution (3.2 mL, 2.0mmol) of n-butyllithium was added while stirring the solution at −40° C.The solution was further stirred for one hour while heating to 0° C.Then, the solution was cooled again to −78° C. After adding a solutionof trimethyl borate (0.52 g, 5.0 mmol) in dry THF (5 mL) dropwise, thesolution was stirred at room temperature for 5 h. After adding a 1 Nhydrochloric acid (20 mL), the stirring was continued for one hour, andthen the aqueous layer was removed.

The organic layer was dried over magnesium sulfate and the solvent wasevaporated off under reduced pressure. The obtained solid was washedwith toluene to obtain a white solid (0.66 g). The yield was 72%.

(8) Synthesis of Aromatic Heterocyclic Derivative (E1)

Under argon atmosphere, into a mixture of the intermediate 7 (0.66 g,1.4 mmol), 2-chloro-4,6-diphenyltriazine (0.40 g, 1.5 mmol), andPd[PPh₃]₄ (tetrakis(triphenylphosphine)palladium) (0.033 g, 0.029 mmol),toluene (5 mL), dimethoxyethane (5 mL) and a 2 M aqueous solution ofNa₂CO₃ (5 mL, 10.0 mmol) were added. The resultant mixture was stirredfor 10 h while refluxing under heating.

After the reaction, the reaction liquid was cooled to room temperatureand extracted with dichloromethane in a separating funnel. The organiclayer was dried over MgSO₄, filtered, and concentrated. The obtainedresidue was purified by silica gel column chromatography to obtain awhite solid (0.66 g), which was identified as the following aromaticheterocyclic derivative (E 1) by FD-MS analysis (Field Desorption MassSpectrometry) (m/e=647 for molecular weight of 647.76). The yield was71%.

Synthesis Example 2 (Synthesis of Aromatic Amine Derivative (B1)) (1)Synthesis of Intermediate 8

Under argon atmosphere, into a solution of the intermediate 5 (2.8 g,6.7 mmol) in dichloromethane (22 mL), a solution of bromine (1.8 g, 11.2mmol) in dichloromethane (36 mL) was added dropwise under cooling withice. The reaction was allowed to proceed overnight. After adding anaqueous solution of sodium hydrogen carbonate, the reaction mixture wasextracted with dichloromethane and the solvent was evaporated off underreduced pressure. The obtained residue was purified by recrystallizationto obtain a white solid (1.1 g), which was identified as the followingintermediate 8 by FD-MS analysis (m/e=574 for molecular weight of574.30). The yield was 29%.

(2) Synthesis of Aromatic Amine Derivative (B1)

Under argon atmosphere, into a mixture of bis(4-tert-butylphenyl)amine(1.1 g, 4.0 mmol), the intermediate 8 (1.1 g, 2.0 mmol), Pd₂(dba)₃(0.028 g, 0.03 mmol), P(tBu)₃HBF₄ (0.017 g, 0.06 mmol), and sodiumt-butoxide (0.38 g, 4.0 mmol), anhydrous xylene (10 mL) was added. Theresultant mixture was refluxed for 8 h under heating.

After the reaction, the reaction liquid was cooled to 50° C. andfiltered through celite/silica gel. The filtrate was concentrated. Theobtained residue was purified by silica gel column chromatography toobtain a white solid. The crude product was recrystallized from tolueneto obtain a white crystal (1.3 g), which was identified as the followingaromatic amine derivative (B1) by FD-MS analysis (m/e=975 for molecularweight of 975.35). The yield was 65%.

Example 1

A glass substrate of 25 mm×75 mm×1.1 mm thick having ITO transparentelectrode (product of Geomatec Company) was ultrasonically cleaned inisopropyl alcohol for 5 min and then UV/ozone cleaned for 30 min. Thethickness of ITO transparent electrode was 130 nm.

The cleaned glass substrate having the transparent electrode line wasmounted to a substrate holder of a vacuum vapor deposition apparatus.First, the electron accepting compound HI (acceptor) was vapor-depositedon the surface having the transparent electrode line so as to cover thetransparent electrode line to form a compound HI film with a thicknessof 5 nm.

On the compound HI film, the aromatic amine derivative (compound HT-1)as a first hole transporting material was vapor-deposited to form afirst hole transporting layer with a thickness of 100 nm.

Successively after forming the first hole transporting layer, thearomatic amine derivative (compound HT-2) as a second hole transportingmaterial was vapor-deposited to form a second hole transporting layerwith a thickness of 5 nm.

On the second hole transporting layer, the compound BH (host material)and the compound BD (fluorescent dopant material) were vaporco-deposited to form a light emitting layer with a thickness of 15 nm.The concentration of the compound BD in the light emitting layer was3.0% by mass. The co-deposited film works as a light emitting layer.

Successively after forming the light emitting layer, the compound E1 wasdeposited into a thickness of 5 nm. The compound E1 film works as afirst electron transporting layer.

On the first electron transporting layer, the compound ET-2 and Liq wereco-deposited to form a second electron transporting layer with athickness of 25 nm. The concentration of Liq in the second electrontransporting layer was 50% by mass.

Next, Liq was vapor-deposited at a film-forming speed of 0.1 Å/min toform an electron injecting electrode (cathode) with a thickness of 1 nm.On the Liq film, metallic Al was vapor-deposited to form a metalliccathode with a thickness of 80 nm.

The organic EL device of Example 1 has the layered structure: ITO (130nm)/HI (5 nm)/HT-1 (100 nm)/HT-2 (5 nm)/BH:BD (15 nm; 3% by mass)/E1 (5nm)/ET-2:Liq (25 nm; 50% by mass)/Liq (1 nm)/Al (80 nm).

Evaluation of Device Performance

The obtained organic EL device was evaluated for the followingproperties. The results are shown in Table 1.

(1) Driving Voltage (V)

The voltage (unit of measure: V) when an electric current was passedbetween the ITO transparent electrode and the metallic Al cathode so asto obtain a current density of 10 mA/cm² was measured.

(2) External Quantum Efficiency (EQE (%))

A spectral radiance spectrum when applying a voltage to the device so asto obtain a current density of 10 mA/cm² was measured by using aspectroradiometer CS-1000 manufactured by Konica Minolta.

Assuming that Lambertian emission occurred, the external quantumefficiency (EQE) (unit of measure: %) was calculated from the obtainedspectral radiance spectrum.

Comparative Examples 1 and 2

Each organic EL device was produced in the same manner as in Example 1except for using the comparative compounds 1 or 2 in place of thecompound E 1 and evaluated in the same manner as in Example 1. Theresults are shown in Table 1.

TABLE 1 Material of Current density: 10 mA/cm² first electron VoltageEQE transporting layer (V) (%) Example 1 E1 3.50 9.7 ComparativeComparative 3.56 9.2 example 1 compound 1 Comparative Comparative 3.708.7 example 2 compound 2

The organic EL device having the comparative compound 1 or 2 in theelectron transporting layer was operated at a low voltage and had a highefficiency among the devices known in the art. However, the organic ELdevice having the compound E1 in the electron transporting layer wasoperated at an even lower voltage and had an even higher efficiency.

Example 2

A glass substrate of 25 mm×75 mm×1.1 mm thick having ITO transparentelectrode (product of Geomatec Company) was ultrasonically cleaned inisopropyl alcohol for 5 min and then UV/ozone cleaned for 30 min. Thethickness of ITO transparent electrode was 130 nm.

The cleaned glass substrate having the transparent electrode line wasmounted to a substrate holder of a vacuum vapor deposition apparatus.First, the electron accepting compound HI (acceptor) was vapor-depositedon the surface having the transparent electrode line so as to cover thetransparent electrode line to form a compound HI film with a thicknessof 5 nm.

On the compound HI film, the aromatic amine derivative (compound HT-3)as a first hole transporting material was vapor-deposited to form afirst hole transporting layer with a thickness of 100 nm.

Successively after forming the first hole transporting layer, thearomatic amine derivative (compound HT-2) as a second hole transportingmaterial was vapor-deposited to form a second hole transporting layerwith a thickness of 5 nm.

On the second hole transporting layer, the compound BH (host material)and the compound B1 (fluorescent dopant material) were vaporco-deposited to form a light emitting layer with a thickness of 25 nm.The concentration of the compound B1 in the light emitting layer was4.0% by mass. The co-deposited film works as a light emitting layer.

Successively after forming the light emitting layer, the compound ET-3was deposited into a thickness of 10 nm. The compound ET-3 film works asa first electron transporting layer.

On the first electron transporting layer, the compound ET-4 wasvapor-deposited to form a second electron transporting layer with athickness of 15 nm.

Next, LiF was vapor-deposited at a film-forming speed of 0.1 Å/min toform an electron injecting electrode (cathode) with a thickness of 1 nm.On the LiF film, metallic Al was vapor-deposited to form a metalliccathode with a thickness of 80 nm.

The organic EL device of Example 2 has the layered structure: ITO (130nm)/HI (5 nm)/HT-3 (100 nm)/HT-2 (5 nm)/BH:B1 (25 nm; 4% by mass)/ET-3(10 nm)/ET-4 (15 nm)/LiF (1 nm)/Al (80 nm).

Evaluation of Device Performance

The obtained organic EL device was evaluated for the followingproperties. The results are shown in Table 2.

(1) External Quantum Efficiency (EQE (%))

A spectral radiance spectrum when applying a voltage to the device so asto obtain a current density of 10 mA/cm² was measured by using aspectroradiometer CS-1000 manufactured by Konica Minolta.

Assuming that Lambertian emission occurred, the external quantumefficiency (EQE) (unit of measure: %) was calculated from the obtainedspectral radiance spectrum.

(2) Lifetime (LT95)

The device was continuously operated by a direct current at an initialcurrent density of 50 mA/cm². The time taken until the luminance wasreduced to 95% of the luminance when starting the test was measured. Themeasured time was employed as the lifetime (LT95).

Comparative Example 3

An organic EL device was produced in the same manner as in Example 2except for using the comparative compound 3 as the dopant material inplace of the compound B1 and evaluated in the same manner as inExample 1. The results are shown in Table 2.

TABLE 2 Current density: Current density: 10 mA/cm² 50 mA/cm² Dopant EQELifetime LT95 material (%) (%) Example 2 B1 7.5 192 ComparativeComparative 4.7 159 example 3 compound 3

As compared with the device using the comparative compound 3 as thedopant, the organic EL device using the compound B1 as the dopant has ahigher efficiency and a longer lifetime.

REFERENCE SIGNS LIST

-   1: Organic electroluminescence device-   2: Substrate-   3: Anode-   4: Cathode-   5: Light emitting layer-   6: Hole injecting layer/hole transporting layer-   7: Electron injecting layer/electron transporting layer-   10: Emission unit

1. A compound of formula (2-1), (2-2), (2-3), (2-4) (2-5), (2-6) and 2-8)):

wherein: each of R¹ and R² is independently a hydrogen atom, a fluorine atom, a cyano group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted fluoroalkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted fluoroalkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted aryloxy group having 6 to 30 ring carbon atoms, a substituted or unsubstituted alkylthio group having 1 to 20 carbon atoms, a substituted or unsubstituted arylthio group having 6 to 30 ring carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having 5 to 30 ring carbon atoms, or a group represented by —Si(R₁₀₁)(R₁₀₂)(R₁₀₃) or a group represented by —Z—R^(a); R¹'s and R²'s, if present, may be the same or different, and R¹'s and R²'s may be bonded to each other to form a ring structure, respectively; Z is a single bond, a substituted or unsubstituted arylene group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroarylene group having 5 to 30 ring atoms, or a divalent linking group wherein two to four groups selected from the arylene group and the heteroarylene group are linked together; Z′ s, if present, may be the same or different; R^(a) is a substituted or unsubstituted aryl group having 6 to 30 carbon atoms each of n1 and n2 is an integer of 0 to 4; R^(a)'s, if present, may be the same or different; each of R¹¹ to R¹⁶, R²¹ to R²⁶, R³¹ to R³⁸, and R⁴¹ to R⁴⁸ is independently a hydrogen atom, a fluorine atom, a cyano group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted fluoroalkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted fluoroalkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted aryloxy group having 6 to 30 ring carbon atoms, a substituted or unsubstituted alkylthio group having 1 to 20 carbon atoms, a substituted or unsubstituted arylthio group having 6 to 30 ring carbon atoms, a group represented by —Si(R₁₀₁)(R₁₀₂)(R₁₀₃), or a group represented by —Z—R^(a); each of R₁₀₁ to R₁₀₃ is independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms, or a substituted or unsubstituted heteroaryl group having 5 to 50 ring atoms; provided that at least one of R¹¹ to R¹⁶ and R²¹ to R²⁶ of each of formulae (2-1), (2-2), (2-3), (2-4), (2-5), and (2-6) is a group represented by —Z—R^(a); at least one of R¹¹ to R¹⁶ and R³¹ to R³⁸ of formula (2-8) is a group represented by —Z—R^(a); adjacent two selected from R¹¹ to R¹⁶, R²¹ to R²⁶, R³¹ to R³⁸, and R⁴¹ to R⁴⁸ may be bonded to each other to form a ring structure.
 2. The compound according to claim 1, wherein the compound is represented by any of formulae (2-1) to (2-6); each of R¹¹ to R¹⁶ and R²¹ to R²⁶ is independently a hydrogen atom, a fluorine atom, a cyano group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted fluoroalkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted fluoroalkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted aryloxy group having 6 to 30 ring carbon atoms, a substituted or unsubstituted alkylthio group having 1 to 20 carbon atoms, a substituted or unsubstituted arylthio group having 6 to 30 ring carbon atoms, a group represented by —Si(R₁₀₁)(R₁₀₂)(R₁₀₃), or a group represented by —Z—R^(a); provided that at least one of R¹¹ to R¹⁶ and R²¹ to R²⁶ of each of formulae (2-1), (2-2), (2-3), (2-4), (2-5), and (2-6) is a group represented by —Z—R^(a); R¹'s and R²'s, if present, may be the same or different, and R¹'s and R²'s may be bonded to each other to form a ring structure, respectively; and adjacent two selected from R¹¹ to R¹⁶ and R²¹ to R²⁶ may be bonded to each other to form a ring structure.
 3. A material for organic electroluminescence devices comprising the compound according to claim
 1. 4. An organic electroluminescence device comprising an organic thin film layer which comprises one or more layers and is disposed between a cathode and an anode, wherein the organic thin film layer comprises a light emitting layer and at least one layer of the organic thin film layer comprises the compound according to claim
 1. 5. The organic electroluminescence device according to claim 4, wherein the light emitting layer comprises the compound.
 6. The organic electroluminescence device according to claim 4, wherein the at least one layer comprises the compound and an anthracene derivative represented by formula (5):

wherein: each of Ar¹¹ and Ar¹² is independently a substituted or unsubstituted monocyclic group having 5 to 50 ring atoms or a substituted or unsubstituted fused ring group having 8 to 50 ring atoms; and each of R¹⁰¹ to R¹⁰⁸ is independently a group selected from a hydrogen atom, a substituted or unsubstituted monocyclic group having 5 to 50 ring atoms, a substituted or unsubstituted fused ring group having 8 to 50 ring atoms, a group comprising a combination of the monocyclic group and the fused ring group, a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 50 ring carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 50 carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 50 carbon atoms, a substituted or unsubstituted aryloxy group having 6 to 50 ring carbon atoms, a substituted or unsubstituted silyl group, a halogen atom, and a cyano group.
 7. The organic electroluminescence device according to claim 4, wherein the organic thin film layer comprises an electron transporting layer and the electron transporting layer comprises the compound.
 8. The organic electroluminescence device according to claim 4, wherein the organic thin film layer comprises a hole transporting layer and the hole transporting layer comprises the compound.
 9. The organic electroluminescence device according to claim 4, wherein the organic thin film layer comprises an electron transporting layer and a blocking layer between the electron transporting layer and the light emitting layer, and the blocking layer comprises the compound.
 10. An electronic device comprising the organic electroluminescence device according to claim
 4. 